Clownfish fry died after transfer - why?

[Formulator]

Traffic is low on the fish breeding forum, so hoping to get some input on here so I can apply learnings tonight.

I killed about 15 clownfish fry that hatched last night and have some questions about what may have gone wrong.

Only about 10% of the eggs hatched, and they are still looking nice and silvery in the parents’ tank so I’m hoping to have better success with the rest, assuming they all hatch tonight.

My setup for the larvae/fry tank is a 10 gallon aquarium, blacked out on all sides, filled slightly less than halfway with water from the parent tank at salinity 1.026. I have had a rotifer culture going for about a week which has been growing great using roti-green complete for food. About an hour before expected hatch, I harvested a gallon of rotifers, strained them and added to the fry tank. I tinted the tank water with a few mL of RG complete that I mixed in some saltwater prior to adding. My light is an LED light bar which I turned to the lowest white setting and placed on the corner of the tank so that it was only partially shining on the water and the opposite side of the tank stayed pretty dark.

After hatch in the parent tank, I used a vossen trap to catch the fry. I only caught 15-20 fry and the rest of the eggs did not hatch. I shined a dim light on the eggs to check on them a few times (probably a mistake).

After transferring the larvae to their new home, many immediately started swimming in erratic circles, but a few looked alright so I left them alone for about 30 minutes. After that 30 minutes I went back to check on them and all were dead.

It is noteworthy that I only had one air pump and had to use it for the vossen trap, so the fry tank had no aeration for about 3 hours before adding the fry.

So, what are your thoughts? Did I shock them with too much light? Did the lack of aeration suffocate them and/or the rotifers, leading to ammonia spike? Is there a problem with using RG complete for tinting? Can particulate matter in the tank kill fry? I had some minor dust fall in the tank from a basement shelf above. Can minor temperature differences (1-2 degrees) between parent and fry tank cause shock? I set the heater to same set point but didn’t verify the tanks were matching with a thermometer. Any other suggestions?

 

[Formulator]

Bump

 

[Bj’s Reef]

Following.

 

[Uncle99]

It’s not uncommon for a few eggs to hatch early.

Newly hatched fry are super delicate and may have been damaged in the trap.

Transferring from one tank to another is difficult as so much may be different.

I have found better success in leaving the fry where they hatched, and moving the parents.

I split the tank in half, split by a screen which allows the easy pass by fry but not the parents.

Two hours after dark, I shine a pin point light on the side opposite the eggs, so when they hatch, the fry run to the light, through the screen, safe from parents.

About 3 hours after dark, when most eggs hatched, I transfer the parents to a new breeding tank, the the old breeding tank becomes the fry rearing tank.

I use the same procedure on shrimp rearing. A pic of the tank and fry below.

Everyone has a different way, I’m not sold on the Vossen trap, but again, I’ve never used one.

Good luck on the next round!

 

[MTracyRN]

I personally prefer to use rotigreen omega mixed with water to tint because it has less additives than rgcomplete. I feed RGcomplete bc the additives reduce bubbles and ammonia in the rotifer culture. Another thing I would say is assuming your rearing tank is a 10 gallon (I prefer to start with 4 gallons of water and add slowly up to 6 gal total) 1 gallon worth of rotifers is too much. I use 32oz worth for the first night of the hatch and assess if i need to add more in the next morning. Chances are the rotifer population will maintain itself on its own for at least the first 48 hours. 1 gallon is a lot of rotifers and they are most likely sucking up all the oxygen. Best of luck.

 

[Formulator]

It’s not uncommon for a few eggs to hatch early.

Newly hatched fry are super delicate and may have been damaged in the trap.

Transferring from one tank to another is difficult as so much may be different.

I have found better success in leaving the fry where they hatched, and moving the parents.

I split the tank in half, split by a screen which allows the easy pass by fry but not the parents.

Two hours after dark, I shine a pin point light on the side opposite the eggs, so when they hatch, the fry run to the light, through the screen, safe from parents.

About 3 hours after dark, when most eggs hatched, I transfer the parents to a new breeding tank, the the old breeding tank becomes the fry rearing tank.

I use the same procedure on shrimp rearing. A pic of the tank and fry below.

Everyone has a different way, I’m not sold on the Vossen trap, but again, I’ve never used one.

Good luck on the next round!

I personally prefer to use rotigreen omega mixed with water to tint because it has less additives than rgcomplete. I feed RGcomplete bc the additives reduce bubbles and ammonia in the rotifer culture. Another thing I would say is assuming your rearing tank is a 10 gallon (I prefer to start with 4 gallons of water and add slowly up to 6 gal total) 1 gallon worth of rotifers is too much. I use 32oz worth for the first night of the hatch and assess if i need to add more in the next morning. Chances are the rotifer population will maintain itself on its own for at least the first 48 hours. 1 gallon is a lot of rotifers and they are most likely sucking up all the oxygen. Best of luck.

Thank you both for the suggestions! I was able to keep about 10 fry alive for 2.5 days from the main hatch after the night 1 partial hatch failure. I think the rotigreen complete was at least partially to blame because the die off happened within 30 minutes of adding more tint on day 2.

I haven’t tried again yet because my dog was diagnosed with cancer and unfortunately we just lost him, but I’m thinking I will give it another go next week.

I’m really set on not moving the parents out of my display and not really looking to make money on this whole ordeal, so not overly concerned about losing some to the vossen trap. Though if this time is a failure, I might consider moving the parents. For now, I will reduce rotifers and switch to rotigreen omega for the fry tank. Since that does not contain the ammonia binder, do you use a product like Prime or Ammo-lock?

 

[MTracyRN]

Thank you both for the suggestions! I was able to keep about 10 fry alive for 2.5 days from the main hatch after the night 1 partial hatch failure. I think the rotigreen complete was at least partially to blame because the die off happened within 30 minutes of adding more tint on day 2.

I haven’t tried again yet because my dog was diagnosed with cancer and unfortunately we just lost him, but I’m thinking I will give it another go next week.

I’m really set on not moving the parents out of my display and not really looking to make money on this whole ordeal, so not overly concerned about losing some to the vossen trap. Though if this time is a failure, I might consider moving the parents. For now, I will reduce rotifers and switch to rotigreen omega for the fry tank. Since that does not contain the ammonia binder, do you use a product like Prime or Ammo-lock?

I start adding prime (1mL per 5 gal) around day 3-5, ammonia badges are super helpful in catching ammonia spikes early.

 

[ISpeakForTheSeas]

Since that does not contain the ammonia binder, do you use a product like Prime or Ammo-lock?

I start adding prime (1mL per 5 gal) around day 3-5

Just to put this out there - Prime and other products don't seem to actually do anything for ammonia:

By all accounts I can find, no, Prime and other conditioners will not actually detoxify ammonia (Randy Holmes-Farley has written about this a few times on the forum now, and a few others have done some testing on the topic too):

Like the claims about Prine, I am not convinced it does anything useful.

I’d love to know if it does anything useful. Don’t be fooled into assuming all hobby products do what they claim. Some some do not.

Does Prime actually "Detoxify" free ammonia, NH3?

This started when @Dan_P was looking at measuring NH3 with seneye and was curious about performance near zero NH3. I suggested trying Prime to artificially zero out the NH3 sensor, and the results were weird... so I checked with my seachem kit. Prime by Seachem is commonly used to treat tap...

www.reef2reef.com

Prime Does Not Remove Ammonia

Last August we discussed data that cast doubt on the ability of Prime to remove ammonia from artificial seawater. https://www.reef2reef.com/threads/does-prime-actually-detoxify-free-ammonia-nh3.849985/ Since then, I continued the search for evidence that Prime removed ammonia from artificial...

www.reef2reef.com

The links talk about that (posts 9, 13, and 14 in the second thread are particularly good); and yes, most test kits - including the one recommended by Seachem - can't read any difference between water with prime and water without (post 14 discusses this too).

As mentioned in the threads, probably the best way to tell for sure would be to run a controlled ammonia toxicity test using live specimens, but that runs into some ethical concerns, and to my knowledge hasn't been attempted yet (someone on the Humblefish forums technically ran a semi-serious test, but the shrimp were fine in all three conditions, so it's pretty safe to say they didn't add enough ammonia to begin with for a toxicity test).

How toxic is ammonia, really?

In the context of trying to understand why so many people believe Seachem Prime was useful for them in an elevated ammonia situation, against the data in the link below about Prime potentially doing nothing to free ammonia in seawater, the question arises, why...

www.reef2reef.com

 

[Formulator]

Just to put this out there - Prime and other products don't seem to actually do anything for ammonia:

How toxic is ammonia, really?

In the context of trying to understand why so many people believe Seachem Prime was useful for them in an elevated ammonia situation, against the data in the link below about Prime potentially doing nothing to free ammonia in seawater, the question arises, why...

www.reef2reef.com

I’ve seen those discussions but still not buying it. I think the detection methods in the home experiments are more likely not up to the task of determining the difference between complexed ammonia and the ionic form. The experience of hundreds of breeders conflicts with the conclusions of these “controlled” experiments.

 

[exnisstech]

I haven’t tried again yet because my dog was diagnosed with cancer and unfortunately we just lost him, but I’m thinking I will give it another go next week.

My condolences on your loss.

 

[Formulator]

My condolences on your loss.

Thank you. He was a great dog. 13 years not bad for a giant.

 

[ISpeakForTheSeas]

I’ve seen those discussions but still not buying it. I think the detection methods in the home experiments are more likely not up to the task of determining the difference between complexed ammonia and the ionic form. The experience of hundreds of breeders conflicts with the conclusions of these “controlled” experiments.

That's fair to be skeptical- it does present us with a good experiment opportunity if you're willing though: once you've figured out a way to consistently raise the fry (presumably while still using Prime), try raising them the exact same way without the Prime and see if the results change in any meaningful way; document the results of both with Prime and without and let us know how it goes- if there's a difference in results and it can't be explained beyond the presence or absence of Prime, then we can view that as evidence of it doing something (presumably something positive at this point).

Ideally, you'd raise at least three batches of fry each way to make sure there's not some sort of error or unnoticed confounding variable.

I recognize this would take months to do properly unless you happen to have several replicate tanks available, but it would be interesting to see.

 

[Formulator]

That's fair to be skeptical- it does present us with a good experiment opportunity if you're willing though: once you've figured out a way to consistently raise the fry (presumably while still using Prime), try raising them the exact same way without the Prime and see if the results change in any meaningful way; document the results of both with Prime and without and let us know how it goes- if there's a difference in results and it can't be explained beyond the presence or absence of Prime, then we can view that as evidence of it doing something (presumably something positive at this point).

Ideally, you'd raise at least three batches of fry each way to make sure there's not some sort of error or unnoticed confounding variable.

I recognize this would take months to do properly unless you happen to have several replicate tanks available, but it would be interesting to see.

I was thinking the same. I just chimed in on Randy’s thread you shared with some thoughts. I also proposed a hypothetical mechanism by which the typical ammonia test kit would falsely measure iminium salt (the product of Prime’s detoxification reaction) as ammonia.