Blue Tang Died In Less Than 3 Days After Buying - Educational

[Riggins76]

I am posting here as an education for all young hobbyist as well as my own education. So please understand that I know I probably shouldn't have put a Blue Tang in a 37 gallon tank as I have done plenty of research on the minimum size needed for a Blue Tang. I want to understand the why and and not make the same mistake again. Constructive criticism is wanted not chastisement.

Tank Parameters:
37 gallon - 12"D x 22"H x 30"W
Used Doctor Tim's with the 2 Clowns you see in one of the pictures below. Started the cycle on 7/19/2023. The Tank is fully cycled (or so I assume) as the Ammonia, Nitrites, and Nitrates were all 0 on the day I put the Tang in. See below for the list of readings for tank over the last 3 weeks which is when I put the first Clown Fish in. Tank has dry rock in it, a hang on back (HOB) TopFin 50 gallon (newer version) with the surface skimmer, and the carbon bag. Put fresh carbon in the system and took the old out the day I brought the fish home. Cleaned both sponge filters that come with the system the same day. Didn't clean the bio media ceramic rings that the TopFin filter came with as I assumed it probably had a lot of beneficial bacteria on it. Tank also has a Jebao MP70 Crossflow (would like to start reefing oneday). I have used it sporadically because I have read that it can help with fish exercise however I have some questions further in this post specific to pumps and FOWLR tanks. I have air pump, pumping through a secondary sponge filter. It has been going pretty much continuously since I started cycling the tank.

The day I brought the Tang home I also brought home 2 other fish, a Flame Hawkfish and a Yellow Watchman Goby. As you can see the ammonia and nitrates both went up over the last 2 days which is expected considering new bio load and I haven't checked this morning but I assume ammonia could be around .25 or .5. I will check this evening and report back. The blue tang as you can see is roughly 1-2 inches in length. My plan was to grow him a couple inches this year maybe up to 4 and then buy a bigger tank like a 100 gallon or so. As I have mentioned I understand the size of the tank does not match the size of the fish but the fellow at the fish store said that the tang would be fine for the first couple of years. I took his word for it because I was eager (as well as wanted to show the Tang to my kids) and figured I would just see if I could keep the fish alive for that long. Apparently not which is very disheartening.

I do not have a quarantine tank. I have one ready to go but I don't have a filter and have a question about that later on in this post. Having said that, I floated all the fish for roughly 30 min and then acclimated via the bag for another 1-1.5 hours based on the amount of water in each of their individual bags. I released them and immediately the Blue Tang stuck his head under a rock and laid on his side. It had a whiteish hue on its belly right out of the bag and didn't really think anything of it at first and thought maybe it was light so Ill give it until morning. I fed all the fish that night Mysis Shrimp. I don't think the Tang ate but he wasn't near any of the other fish and I fed him separately. I did see him put some shrimp in his mouth but he spit it out quickly, so I assumed he had eaten at least a little but maybe not. Monday evening I fed the fish Mysis Shrimp again and again I saw him put some food in his mouth and spit it out so I am not sure if he ate anything that night either. He was swimming around the tank Monday night and nothing appeared to be wrong although I still did see the white hue on his belly. Again I thought it might be the light.

I did some research and found out they like Green Nori, so I bought some on Tuesday. When I got home from work, the fish just appeared to be hiding but also not moving at all, almost as if he was dead. I did see a little tail wag and gills moving so I knew he was alive but probably just hiding behind the rocks close to the bottom. You will notice the Nori holder on the far right bottom of the tank (blue clip). This is basically where he was ate last night when I fed the fish. All the other fish were on the left side of the tank (expect Yellow Goby I have no idea where he is. Assume he is under the rock in the back based on all the research I have done), and I fed them all Mysis Shrimp, then put that Nori right beside him. He didn't move whatsoever when I put my hand that close to him, so I knew something was wrong. I research the white hue and realized it may be a problem and figured I would resolve it today. After all the other fish had eaten and the Blue Tang was still down in the bottom of the tank I turned the Jebao on to circulate water so that the food would get sucked up by the filter. When I did this, I walked off and came back 5 min later and noticed that the water circulation was pushing the fish all over the tank and he wasn't able to swim past the current like he was both days prior. I turned off the pump and he fell straight to the rock. He was still breathing last night at around 12:00 pm, but didn't move his head out of the rocks. I assumed the worst but went to bed and this morning he wasn't breathing.

For clarity, I watched the fish pretty well all day Sunday, and was able to work from home on Monday and watch the fish all day Monday. All the fish got along, and not a single fight broke out that I saw.

Suffice to say I don't know what caused him to die and would like to understand from the masses what the cause might be. Here are my thoughts/questions

1. Tank might not be fully cycled - I don't think this could be the case because if it wasn't cycled, then how can other fish be tolerating it so well? How long would it take for it to be fully cycled for this type of fish? I have read your tank never really finishes cycling which makes sense, but when does a tank become truly fully established if not now?

2.Fish Tank was too small and the fish became stressed - I am a newbie but I still don't understand how this could be the case. I might be missing something but typically I have heard quarantine tanks being like 10 gallons, and if that is the size of the quarantine tank that I am supposedly supposed to put them in prior to my display tank, how does it make any sense that they require a bigger tank?

3. Too many fish all at once - I don't know if this could be it but maybe Blue Tangs can't handle that large of an ammonia spike that early on? .25 doesn't seem like that much and all the other fish don't seem to be having issues in the slightest.

4. Could it have been that there was something already wrong with the fish when I brought it home? I don't know all the diseases out there but it certainly looked like a healthy fish with the exception of the whitish hue.

5. Any parameter issue that sticks out to you? FYI the last salinity reading from yesterday was read from my new digital tester so it may be a fuzz off on calibration. 29 doesn't seem that low comparatively

6. Not related but semi related - can I run my pump continously throughout the day/night? or will that tire the fish out some much that they become exausted? I have mine running at 40% which is I believe 40% of the maximum rating of the pump itself but I could be wrong.

7. Any other comments that may help me understand what I may have done wrong?

Again I am not looking forchastisement as that deters people away from the hobby. I am really looking for help and want to understand so any help would be appreciated.

 

[blaxsun]

These are just some quick (general) observations based on your questions.

1. If the tank wasn't cycled properly all your other fish would be dead.
2. 37 gallons is to small for a tang mid to long-term. I don't think the size was necessarily a contributing factor, though.
3. Without knowing your actual ammonia level it would be hard to speculate.
4. Yes, it's possible.
5. Salinity is definitely way too low.
6. Yes, your pump needs to run constantly so you can achieve good filtration and oxygenation in your tank.

 

[Lahey]

I don't think your tank is fully cycled. A new tank without a large amount of live rock from an existing tank will take more than 3 weeks to cycle. Adding an additional 3 fish was too much and caused an ammonia spike. Patience is key when setting up a new tank.

 

[Riggins76]

I don't think your tank is fully cycled. A new tank without a large amount of live rock from an existing tank will take more than 3 weeks to cycle. Adding an additional 3 fish was too much and caused an ammonia spike. Patience is key when setting up a new tank.

Thanks for your insite. I will take this into consideration before adding new fish (if any) next time.

 

[Riggins76]

These are just some quick (general) observations based on your questions.

1. If the tank wasn't cycled properly all your other fish would be dead.
2. 37 gallons is to small for a tang mid to long-term. I don't think the size was necessarily a contributing factor, though.
3. Without knowing your actual ammonia level it would be hard to speculate.
4. Yes, it's possible.
5. Salinity is definitely way too low.
6. Yes, your pump needs to run constantly so you can achieve good filtration and oxygenation in your tank.

Thanks for your insite. I appreciate it. I will certianly add more salt. I forgot to mention, I am performing a water change this morning because of the dead fish. Not a big, like 5-10% but one none the less so I will make sure to try and change the salinity a bit.

 

[blaxsun]

Thanks for your insite. I will take this into consideration before adding new fish (if any) next time.

Hold off adding any new fish until you get your salinity and other water parameters balanced to where they need to be. Slow and steady wins the race...

 

[jda]

There is no chance that your tank was cycled, as in done-done, but it probably was at a place where it could handle some fish waste. It can take several months, or longer, for a tank to get closer to fully cycled where it is dynamic and ready to handle almost anything.

This is an important distinction since ecosystems from fully cycled tanks are easier on fish than earlier stages. Captive bred fish are better at living in semi-sterlie tanks than wild fish and also tanks with less than ideal parameters. While your tank is still growing and developing into the cycle, focus on the clownfish and patience - I know that nobody like to hear patience, but it does work.

The fish could have had issues before you got it. They can also be stressed from salinity jumps - I would keep your tank at 35 ppt unless you have a really good reason not to, and then you need to get good at acclimation and forgo many inverts that cannot handle hypo salinity.

Even if ammonia spikes do not instantly kill fish, they can damage gills for a lifetime. Some are more resilient than other. Too many of the so-called cycle geniuses think that non-fish-death is a success but only time tells the whole tale and fish are not able to call a 1-800 lawyer for asbestos or harmful gas exposure to their lungs.

Just go slow. Feed these fish smartly. Let some algae develop. Get the salinity to reef levels. Get a few snails and crabs. Get some real live rock if you are so inclined to speed things up. Then, get some more fish after you see more of an ecosystem develop.

That dead/dry rock is likely to have diatom and hair algae issues, so be ready for that. It sucks, but you can get through it.

None of this addresses what you are going to do for disease, so have a plan for this too. I don't get too preachy on this since there are many ways to get this done, and some better suited for beginners than others, but real diverse ocean live rock that has a good amount of microfauna on it can indeed eat/hinder fish disease tomonts as they drop off of the fish for parts of their lifecycle.

 

[Riggins76]

the so-called cycle geniuses think that non-fish-death is a success but

There is no chance that your tank was cycled, as in done-done, but it probably was at a place where it could handle some fish waste. It can take several months, or longer, for a tank to get closer to fully cycled where it is dynamic and ready to handle almost anything.

This is an important distinction since ecosystems from fully cycled tanks are easier on fish than earlier stages. Captive bred fish are better at living in semi-sterlie tanks than wild fish and also tanks with less than ideal parameters. While your tank is still growing and developing into the cycle, focus on the clownfish and patience - I know that nobody like to hear patience, but it does work.

The fish could have had issues before you got it. They can also be stressed from salinity jumps - I would keep your tank at 35 ppt unless you have a really good reason not to, and then you need to get good at acclimation and forgo many inverts that cannot handle hypo salinity.

Even if ammonia spikes do not instantly kill fish, they can damage gills for a lifetime. Some are more resilient than other. Too many of the so-called cycle geniuses think that non-fish-death is a success but only time tells the whole tale and fish are not able to call a 1-800 lawyer for asbestos or harmful gas exposure to their lungs.

Just go slow. Feed these fish smartly. Let some algae develop. Get the salinity to reef levels. Get a few snails and crabs. Get some real live rock if you are so inclined to speed things up. Then, get some more fish after you see more of an ecosystem develop.

That dead/dry rock is likely to have diatom and hair algae issues, so be ready for that. It sucks, but you can get through it.

None of this addresses what you are going to do for disease, so have a plan for this too. I don't get too preachy on this since there are many ways to get this done, and some better suited for beginners than others, but real diverse ocean live rock that has a good amount of microfauna on it can indeed eat/hinder fish disease tomonts as they drop off of the fish for parts of their lifecycle.

Thanks for the in-site. It is sounding like my issue is patience and I just need to bear with it. I will say I did see my first diatom bloom which I hear is a great thing so I was actually kind of excited for that. I also saw what I thought was alge so I plan getting some snails to start combating that.

 

[BigMonkeyBrain]

You stated "Put fresh carbon in the system and took the old out the day I brought the fish home. Cleaned both sponge filters that come with the system the same day."

Cleaning filter media is a mistake for a newly setup aquarium. Nitrifying bacteria was populating the carbon and the sponge filters. Most foods take days or weeks to decompose and the nitrifying bacteria can handle this. The carbon can stay in forever as bacteria likes to grow on it. The filter is fine, a bottom up flow filter arrangement with a coarse sponge and good surface area especially with the inlet sponge filter.

The tang usually would have had a hard time breathing ( usually rapid breathing ) if ammonia was the issue.


Probably happens !

 

[killer2001]

Sounds like an acclimation mishap to me, being that the tang is more sensitive than the other two fish. Typically after you temperature acclimate by floating the bag you want to get them out of the bag water and into a larger volume of water to prevent ammonia burn. When I am expecting a fish, I will get out the 5 gallon bucket and take about 3 gallons of my tank water, and I will dilute down to the salinity the fish is in with RODI. From there, I will drip acclimate back up to the salinity of the tank, this typically takes an hour or two.

 

[littlefoxx]

I am posting here as an education for all young hobbyist as well as my own education. So please understand that I know I probably shouldn't have put a Blue Tang in a 37 gallon tank as I have done plenty of research on the minimum size needed for a Blue Tang. I want to understand the why and and not make the same mistake again. Constructive criticism is wanted not chastisement.

Tank Parameters:
37 gallon - 12"D x 22"H x 30"W
Used Doctor Tim's with the 2 Clowns you see in one of the pictures below. Started the cycle on 7/19/2023. The Tank is fully cycled (or so I assume) as the Ammonia, Nitrites, and Nitrates were all 0 on the day I put the Tang in. See below for the list of readings for tank over the last 3 weeks which is when I put the first Clown Fish in. Tank has dry rock in it, a hang on back (HOB) TopFin 50 gallon (newer version) with the surface skimmer, and the carbon bag. Put fresh carbon in the system and took the old out the day I brought the fish home. Cleaned both sponge filters that come with the system the same day. Didn't clean the bio media ceramic rings that the TopFin filter came with as I assumed it probably had a lot of beneficial bacteria on it. Tank also has a Jebao MP70 Crossflow (would like to start reefing oneday). I have used it sporadically because I have read that it can help with fish exercise however I have some questions further in this post specific to pumps and FOWLR tanks. I have air pump, pumping through a secondary sponge filter. It has been going pretty much continuously since I started cycling the tank.

The day I brought the Tang home I also brought home 2 other fish, a Flame Hawkfish and a Yellow Watchman Goby. As you can see the ammonia and nitrates both went up over the last 2 days which is expected considering new bio load and I haven't checked this morning but I assume ammonia could be around .25 or .5. I will check this evening and report back. The blue tang as you can see is roughly 1-2 inches in length. My plan was to grow him a couple inches this year maybe up to 4 and then buy a bigger tank like a 100 gallon or so. As I have mentioned I understand the size of the tank does not match the size of the fish but the fellow at the fish store said that the tang would be fine for the first couple of years. I took his word for it because I was eager (as well as wanted to show the Tang to my kids) and figured I would just see if I could keep the fish alive for that long. Apparently not which is very disheartening.

I do not have a quarantine tank. I have one ready to go but I don't have a filter and have a question about that later on in this post. Having said that, I floated all the fish for roughly 30 min and then acclimated via the bag for another 1-1.5 hours based on the amount of water in each of their individual bags. I released them and immediately the Blue Tang stuck his head under a rock and laid on his side. It had a whiteish hue on its belly right out of the bag and didn't really think anything of it at first and thought maybe it was light so Ill give it until morning. I fed all the fish that night Mysis Shrimp. I don't think the Tang ate but he wasn't near any of the other fish and I fed him separately. I did see him put some shrimp in his mouth but he spit it out quickly, so I assumed he had eaten at least a little but maybe not. Monday evening I fed the fish Mysis Shrimp again and again I saw him put some food in his mouth and spit it out so I am not sure if he ate anything that night either. He was swimming around the tank Monday night and nothing appeared to be wrong although I still did see the white hue on his belly. Again I thought it might be the light.

I did some research and found out they like Green Nori, so I bought some on Tuesday. When I got home from work, the fish just appeared to be hiding but also not moving at all, almost as if he was dead. I did see a little tail wag and gills moving so I knew he was alive but probably just hiding behind the rocks close to the bottom. You will notice the Nori holder on the far right bottom of the tank (blue clip). This is basically where he was ate last night when I fed the fish. All the other fish were on the left side of the tank (expect Yellow Goby I have no idea where he is. Assume he is under the rock in the back based on all the research I have done), and I fed them all Mysis Shrimp, then put that Nori right beside him. He didn't move whatsoever when I put my hand that close to him, so I knew something was wrong. I research the white hue and realized it may be a problem and figured I would resolve it today. After all the other fish had eaten and the Blue Tang was still down in the bottom of the tank I turned the Jebao on to circulate water so that the food would get sucked up by the filter. When I did this, I walked off and came back 5 min later and noticed that the water circulation was pushing the fish all over the tank and he wasn't able to swim past the current like he was both days prior. I turned off the pump and he fell straight to the rock. He was still breathing last night at around 12:00 pm, but didn't move his head out of the rocks. I assumed the worst but went to bed and this morning he wasn't breathing.

For clarity, I watched the fish pretty well all day Sunday, and was able to work from home on Monday and watch the fish all day Monday. All the fish got along, and not a single fight broke out that I saw.

Suffice to say I don't know what caused him to die and would like to understand from the masses what the cause might be. Here are my thoughts/questions

1. Tank might not be fully cycled - I don't think this could be the case because if it wasn't cycled, then how can other fish be tolerating it so well? How long would it take for it to be fully cycled for this type of fish? I have read your tank never really finishes cycling which makes sense, but when does a tank become truly fully established if not now?

2.Fish Tank was too small and the fish became stressed - I am a newbie but I still don't understand how this could be the case. I might be missing something but typically I have heard quarantine tanks being like 10 gallons, and if that is the size of the quarantine tank that I am supposedly supposed to put them in prior to my display tank, how does it make any sense that they require a bigger tank?

3. Too many fish all at once - I don't know if this could be it but maybe Blue Tangs can't handle that large of an ammonia spike that early on? .25 doesn't seem like that much and all the other fish don't seem to be having issues in the slightest.

4. Could it have been that there was something already wrong with the fish when I brought it home? I don't know all the diseases out there but it certainly looked like a healthy fish with the exception of the whitish hue.

5. Any parameter issue that sticks out to you? FYI the last salinity reading from yesterday was read from my new digital tester so it may be a fuzz off on calibration. 29 doesn't seem that low comparatively

6. Not related but semi related - can I run my pump continously throughout the day/night? or will that tire the fish out some much that they become exausted? I have mine running at 40% which is I believe 40% of the maximum rating of the pump itself but I could be wrong.

7. Any other comments that may help me understand what I may have done wrong?

Again I am not looking forchastisement as that deters people away from the hobby. I am really looking for help and want to understand so any help would be appreciated.

Blue tangs are pretty hardy in my experience. I brought a blue tang home when he was near death and put him in a 32 biocube for treatment. Almost lost the dude twice, once to water quality as tangs are messy and once to brook. I wouldnt put another tang in this tank as its not big enough long term. It looks like your water and stuff was fine per test kits. The blue may not have been healthy when you got him and they are ich magnets. Did you notice any flashing or scratching with him?

 

[Riggins76]

Blue tangs are pretty hardy in my experience. I brought a blue tang home when he was near death and put him in a 32 biocube for treatment. Almost lost the dude twice, once to water quality as tangs are messy and once to brook. I wouldnt put another tang in this tank as its not big enough long term. It looks like your water and stuff was fine per test kits. The blue may not have been healthy when you got him and they are ich magnets. Did you notice any flashing or scratching with him?

I am not sure what flashing is (I looked up some videos but didn't really notice) but I certainly didn't notice him scratching. I am not sure what brook is but I will look it up and let you know if I noticed the symptoms. Thanks for commenting.

 

[Riggins76]

Sounds like an acclimation mishap to me, being that the tang is more sensitive than the other two fish. Typically after you temperature acclimate by floating the bag you want to get them out of the bag water and into a larger volume of water to prevent ammonia burn. When I am expecting a fish, I will get out the 5 gallon bucket and take about 3 gallons of my tank water, and I will dilute down to the salinity the fish is in with RODI. From there, I will drip acclimate back up to the salinity of the tank, this typically takes an hour or two.

Thanks. I will take this into consideration next time I buy a fish. Not planning to buy anymore in the next couple of months.

 

[littlefoxx]

I am not sure what flashing is (I looked up some videos but didn't really notice) but I certainly didn't notice him scratching. I am not sure what brook is but I will look it up and let you know if I noticed the symptoms. Thanks for commenting.

Flashing is where they dart around all crazy essentially. And brook is just what my guy survived, I was explaining how hardy they are. I think your guy either stressed out over the small space or wasnt well when he came to you based on what you described

 

[August]

Im sorry you had a loss on your Blue Hippo Tang.

Food: I know you said you were feeding him Nori and Misy shrimp. Tangs are usually herbivores when they are young, and become carnivores as they get older (I observed this with my own Blue Hippo when he outgrew the tank and would eat anything he could before I relocated him to a new larger home at the LFS. You might have got oversold on mysis shrimp for a new tank either in your research or by an enthusiast who is transitioning from pellet to frozen. Frozen food can have bacteria and other things in it that a new tank may not really be ready to handle. Tangs usually go nuts for algae pellets or those algae disks that drop to the bottom of the tank. The Nori starts to fall apart too quickly before it gets sucked into an overflow.

Acclimation: Another poster talked about this, but I would like to add that sometimes a fish just does not survive the acclimation process because of stress of transport and perhaps the place where he came from might not have been well maintained. I may differ from with other poster suggested being a good practice for you. If you got the tang from a LFS, then the Ammonia burn isn't a thing. That is for when you have transported the critter via mail and it has been out of a established system for several hours. Then, once you expose the water in the bag to air, the burn can begin to start which is why there are articles criticizing drip acclimation methods that have more than 30 minutes for those airborne fish coming in for a landing into your system.
- another side note on this acclimation: Since your whole system is 35 gallons, taking 5 gallons out of it or making 5 gallons of fresh saltwater for your aclimination seems a bit much. If you used freshly mixed saltwater that hadn't dissolved the salt fully, that could have caused issues as well. For a short trip from the LFS, you can float the bags in the tank to acclimate temps and then pour in gradually increasing amounts of water to acclimate the water parameters. (I have noticed that my LFS has lower salinity in their tanks than they have told me I need to keep my setup at, so now I put my probe into the transport bag to see what salinity the fish is coming from.)

Waiting to see if cycle needs to complete: On allowing your tank to cycle, I would also encourage you to put in a little food each day to accliminate your tank to the incoming bioload. Some will say that food that goes into the tank that is not eaten would go against what I first thought I knew from talking to peeps at the LFS. However, fish digestion is not efficient at pulling nutrients from their food and most of the nutrients come right out of the fish leaving your tank nitrogen cycle to do the heavy lifting. I wouldn't feed as much as if there was a fish there, but I would put in the food.

I want to compliment you on using RODI water for your first setup. I skipped this when I first entered the hobby and after I switched to RODI water, I got a lot more success.

On your water flow, you don't want the pump to be so strong that it blows your fish all over the place. You might need to get a different pump or maybe a DC controller that you can dial down to an approperiate level.

You have the sponge filter and I don't have experience with your HoB filter, but it doesn't look like a surface skimmer as you described it. I was very curious by how much foam was in the media area of the HoB filter. I can see why you changed the carbon in the media, because Carbon is usually replaced every 30 days. I would ask if you washed the sponges in the HoB with RODI water, just to cover all of the points where impurities and things toxic can enter the tank. An alternative for your HoB filter would be a canister filter that has a larger biomedia capacity, but honestly I haven't run a smaller tank setup like the one you have, so there is probably better advice on the forms for filteration, but I think your sponge filter should for only for a Fish only tank setup

Someone mentioned diatoms, which you can offset by purchasing some live Copeapods if and when they break out.

Anyway, welcome to the hobby! I really get a kick out of it and I hope that you will as well.

edited for my bad spelling

 

[Riggins76]

Im sorry you had a loss on your Blue Hippo Tang.

Food: I know you said you were feeding him Nori and Misy shrimp. Tangs are usually herbivores when they are young, and become carnivores as they get older (I observed this with my own Blue Hippo when he outgrew the tank and would eat anything he could before I relocated him to a new larger home at the LFS. You might have got oversold on mysis shrimp for a new tank either in your research or by an enthusiast who is transitioning from pellet to frozen. Frozen food can have bacteria and other things in it that a new tank may not really be ready to handle. Tangs usually go nuts for algae pellets or those algae disks that drop to the bottom of the tank. The Nori starts to fall apart too quickly before it gets sucked into an overflow.

Acclimation: Another poster talked about this, but I would like to add that sometimes a fish just does not survive the acclimation process because of stress of transport and perhaps the place where he came from might not have been well maintained. I may differ from with other poster suggested being a good practice for you. If you got the tang from a LFS, then the Ammonia burn isn't a thing. That is for when you have transported the critter via mail and it has been out of a established system for several hours. Then, once you expose the water in the bag to air, the burn can begin to start which is why there are articles criticizing drip acclimation methods that have more than 30 minutes for those airborne fish coming in for a landing into your system.
- another side note on this acclimation: Since your whole system is 35 gallons, taking 5 gallons out of it or making 5 gallons of fresh saltwater for your aclimination seems a bit much. If you used freshly mixed saltwater that hadn't dissolved the salt fully, that could have caused issues as well. For a short trip from the LFS, you can float the bags in the tank to acclimate temps and then pour in gradually increasing amounts of water to acclimate the water parameters. (I have noticed that my LFS has lower salinity in their tanks than they have told me I need to keep my setup at, so now I put my probe into the transport bag to see what salinity the fish is coming from.)

Waiting to see if cycle needs to complete: On allowing your tank to cycle, I would also encourage you to put in a little food each day to accliminate your tank to the incoming bioload. Some will say that food that goes into the tank that is not eaten would go against what I first thought I knew from talking to peeps at the LFS. However, fish digestion is not efficient at pulling nutrients from their food and most of the nutrients come right out of the fish leaving your tank nitrogen cycle to do the heavy lifting. I wouldn't feed as much as if there was a fish there, but I would put in the food.

I want to compliment you on using RODI water for your first setup. I skipped this when I first entered the hobby and after I switched to RODI water, I got a lot more success.

On your water flow, you don't want the pump to be so strong that it blows your fish all over the place. You might need to get a different pump or maybe a DC controller that you can dial down to an approperiate level.

You have the sponge filter and I don't have experience with your HoB filter, but it doesn't look like a surface skimmer as you described it. I was very curious by how much foam was in the media area of the HoB filter. I can see why you changed the carbon in the media, because Carbon is usually replaced every 30 days. I would ask if you washed the sponges in the HoB with RODI water, just to cover all of the points where impurities and things toxic can enter the tank. An alternative for your HoB filter would be a canister filter that has a larger biomedia capacity, but honestly I haven't run a smaller tank setup like the one you have, so there is probably better advice on the forms for filteration, but I think your sponge filter should for only for a Fish only tank setup

Someone mentioned diatoms, which you can offset by purchasing some live Copeapods if and when they break out.

Anyway, welcome to the hobby! I really get a kick out of it and I hope that you will as well.

edited for my bad spelling

Thanks for the post. I really appreciate the detailed analysis. I will take all of this into consideration. The pump doesn't really blow any of the fish around at its lowest setting. I usually turn it on for a couple hours in the evening for exercise and to remove waste through the sponge filter. Sometimes I leave it on overnight and the fish seem to have no issue now at least since I started paying more attention. I will say the pump itself seems to have a mode in which it starts to get really hard flow going so I am looking into that. Again the fish seem to be just fine with the current. As for the RODI, I started this tank with fresh water 4-5 years ago and all of my fish died pretty quickly with in one week about 3 months in. I thought I was just really bad at the hobby but got reinvigorated now that both of my kids are a bit older and I have some more available time. I figured water quality was the primary issue so I said screw it, I will buy myself something nice to get back into it lol. Again thanks for your kind words and detailed analysis.

 

[Mr. Mojo Rising]

I don't see any one thing that killed the fish, I think it comes down to impatience and general inappriopriateness of the tank in its current condition. Its the difference between an ecosystem and a glass box with water in it.

I know others have said it (so don't read if you don't want to), but someone needs to speak on the fishes behalf; cycling with fish is not cool, adding a tang into that small of a tank is not cool, and adding fish that fast to a tank is generally bad news (very lucky there was no disease outbreak).

 

[Riggins76]

I don't see any one thing that killed the fish, I think it comes down to impatience and general inappriopriateness of the tank in its current condition. Its the difference between an ecosystem and a glass box with water in it.

I know others have said it (so don't read if you don't want to), but someone needs to speak on the fishes behalf; cycling with fish is not cool, adding a tang into that small of a tank is not cool, and adding fish that fast to a tank is generally bad news (very lucky there was no disease outbreak).

Thanks for the message. I appreciate the feedback.