Problem with my 38 gallon

Boundava · Oct 17, 2024

I have a 38 gallon which had a Neovespicula depressifrons, 2 clowns, a possum wrasse and a diamond goby along with an assortment of corals and snails.
The Neovespicula depressifrons was about 4 years old and died late July- his body wasn't immediately noticeable due to the live rock and coral. For those that don't know he was venomous. A day after he was missing the other fish all died and as I was pulling them out I found the depressifrons body.
Thinking that the venom is what killed the other fish I did a 90% water change on the tank, cleaned the filter out, rinsed all of the live rock in buckets of new saltwater and refilled the tank with new saltwater. Unfortunately I was a unable to empty all of the water as I have a reverse flow undergravel filter in the tank. I also added carbon to my filter and let the tank run for 2 weeks and then replaced the carbon with a zeolite-carbon blend.
After waiting until early October, I added a test molly to the tank. I acclimated it for 2 hours and it seemed fine, it was swimming around happily in the tank but was nowhere to be seen the next day.

Now while I did the water change I pulled out a piece of rock that had some mushroom corals on it and moved it to my 13 gallon tank which has a leaf fish in it. The rock did nothing to the water quality and the leaf fish was fine and has been fine for the month with the rock.

So I'm hesitant to add anything to this tank. It seems that no fish can go in here again unless I break the whole thing down. I'm not sure why, as the corals and the snails and my brittle sea star are all thriving.

Someone suggested that I possibly didn't acclimate the Molly long enough, as they should be acclimated overnight? The Molly was very happy when I was putting it in the saltwater tank, it didn't seem distressed at all and I watched it for about an hour because it is in a room where I can sit and watch it.

Anyone have any suggestions? It's really hard to try to put a $50-100 fish in the tank just to test it out. My only other option is to find a place to stick the corals while I break down the tank again. Possibly bleach it out, and I'm not sure what to do with the filter. It has a Fluval 307 canister along with the reverse flow under gravel. If I redo the tank I will be removing the undergravel. I'm also unsure whether or not the venom is somehow in the tank and if it adhears the plastics because then I would have to trash my current maker as well.

Anyone dealt with this before or have any suggestions it would be greatly appreciated.

AmazingYocool · Oct 17, 2024

Boundava said:
I have a 38 gallon which had a Neovespicula depressifrons, 2 clowns, a possum wrasse and a diamond goby along with an assortment of corals and snails.
The Neovespicula depressifrons was about 4 years old and died late July- his body wasn't immediately noticeable due to the live rock and coral. For those that don't know he was venomous. A day after he was missing the other fish all died and as I was pulling them out I found the depressifrons body.
Thinking that the venom is what killed the other fish I did a 90% water change on the tank, cleaned the filter out, rinsed all of the live rock in buckets of new saltwater and refilled the tank with new saltwater. Unfortunately I was a unable to empty all of the water as I have a reverse flow undergravel filter in the tank. I also added carbon to my filter and let the tank run for 2 weeks and then replaced the carbon with a zeolite-carbon blend.
After waiting until early October, I added a test molly to the tank. I acclimated it for 2 hours and it seemed fine, it was swimming around happily in the tank but was nowhere to be seen the next day.

Now while I did the water change I pulled out a piece of rock that had some mushroom corals on it and moved it to my 13 gallon tank which has a leaf fish in it. The rock did nothing to the water quality and the leaf fish was fine and has been fine for the month with the rock.

So I'm hesitant to add anything to this tank. It seems that no fish can go in here again unless I break the whole thing down. I'm not sure why, as the corals and the snails and my brittle sea star are all thriving.

Someone suggested that I possibly didn't acclimate the Molly long enough, as they should be acclimated overnight? The Molly was very happy when I was putting it in the saltwater tank, it didn't seem distressed at all and I watched it for about an hour because it is in a room where I can sit and watch it.

Anyone have any suggestions? It's really hard to try to put a $50-100 fish in the tank just to test it out. My only other option is to find a place to stick the corals while I break down the tank again. Possibly bleach it out, and I'm not sure what to do with the filter. It has a Fluval 307 canister along with the reverse flow under gravel. If I redo the tank I will be removing the undergravel. I'm also unsure whether or not the venom is somehow in the tank and if it adhears the plastics because then I would have to trash my current maker as well.

Anyone dealt with this before or have any suggestions it would be greatly appreciated.

was the molly already in a salt water tank? If not, then its was probably not acclimated long enough. I'd throw in a "sacrificial" fish. Something strong like a clown pair, chromis, or damsel. Purigen (a really good gfo) will also help.

If that molly was already in a salt enviorment, then it honestly might have been coincidene. Doing frequent water changes and using GFO's should have removed a lot of the poision. If another fish dies than maybe breaking down the tank wouldnt be a bad idea. Make sure the water tests fine before adding another fish. I hope it goes well!

Boundava · Oct 17, 2024

Yeah I forgot to mention that, I did multiple testing but the whole time the water parameters were fine.
No the Molly was a freshy, I thought a 2-hour slow drip acclimation would be enough but I guess not.

Boundava · Oct 17, 2024

BTW some photos of the tank. It's just getting over a crazy diatom and algae issue.

AmazingYocool · Oct 17, 2024

yea that natural light is gonna make the algae go wild lol

and as for mollys, people from my experience 1-2 days with an airstone and drip acclimator.

Boundava · Oct 17, 2024

In my experience the corals really like the natural light. Fortunately the macro algae has kicked in and like I said before the cyano and the algae issue I had seems to be getting under control.
The Petco near me has a saltwater section so I may see if there's something inexpensive to test the tank out with. Like I said I've got a leaf fish and I got to get him some fresh ghost shrimp for the week so I'll be in the store anyway.

Boundava · Oct 18, 2024

So I went to Petco to grab some ghost shrimp for my leaf fish. While I was there I noticed that they had molly for about $5 and then I'd have to buy an air stone which was about $4, or they had damselfish for $9.99. I don't want to second guess the Molly death on water issues or acclimation issues, so I just got a damselfish.
I also grabbed a net breeder so I can watch the fish. So many times the other fish just die and disappear overnight..so I put the damsel fish in the net breeder and s/he is currently floating around in the tank. I put her/him in about 5:30 and s/he is looking fine right now. I was going to stay up until midnight but I can't so I'm going to hope that s/he will be fine tomorrow morning. That's not to say that I may wake up at like three or four am just to double-check.

So from the photos you should be able to tell it's just scooting around it's little enclosure. Sorry for the darkness, I shut the lights off at 8:00 and I took the photos a little after 11:00 pm.

BTW water parameters are fine.

Boundava · Oct 18, 2024

Yay, so I don't know what has changed in the tank or if there was ever really an issue, but the damsel is still alive and actively swimming around it's little net breeder.

I had forgotten to mention that at the end of September I had purchased a goby for the tank, thinking that enough time had passed since the July incidents. Unfortunately the goby passed overnight. I assume that that was because there was still an issue in the tank, not because there might have been some issues with the fish in the first place. I decided to wait another 2 weeks and then try the molly, but the Molly passed as well. I now understand that it's because my acclimation for the molly wasn't long enough.

I'm really happy to know that I can put some fish in this tank again and not have to strip it down and bleach the whole thing. As well as the nightmare of getting more live rocks, substrate, filter media, possibly the current makers...which is really more money than I can spend right now.

The damsel is still in the little net breeder, it's swimming around a lot though so I probably will go ahead and let it out even though I'm hesitant to.

Thank you for your suggestions. I am still planning on breaking down the tank enough to remove the undergravel filter as it's become more of a hinder than a benefit. The reverse flow pumps are awfully loud and occasionally a sale will get stuck in there and it will rattle. It also seems to just be a breeding around for bristle worms too. At least I don't have to toss anything other than the undergravel filter. I can still keep my rocks and my substrate, although I won't need as much substrate as I currently have.

Thanks again for your feedback and help.