Problems with first attempt raising clownfish

[Formulator]

I killed some clownfish larvae last night and have some questions about what may have gone wrong.

Only about 10-20% 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?

 

[MnFish1]

I have never had an issue with light and clownfish mortality (except catching them on the night of hatching if there is more than one light source). Of course, a diffuse light is probably the best at the start - since newly born fry are more light sensitive. I also tend to use water from the display as compared to newly mixed water - and a sponge filter for aeration in the fry tank. The temperature, etc need to be carefully monitored (as well as pH, etc). Remember the fish need a large amount of 'food' and otherwise pristine water.

One suggestion that can help avoid the issues with the trapping, etc is to see if you can get your clowns to breed on an inert pot, etc - that you can remove on the day of hatching - so that when they fry hatch they are in the fry tank already. (Keep the dish underwater at all times (use a larger container with tank water put that tank with the clowns, transfer the 'thing' the eggs are on put it in the container - take both the container and the egg substrate into the new fry tank - without exposing the fry to air etc.

It may be that this was not a good 'brood' - with only 15-20 fry that hatched - One can have hundreds of fry. The good news is clowns breed often - and you'll perfect your technique with time. Hope this helps

 

[Formulator]

Update: The rest of the eggs hatched 2 nights ago and I caught about 50 fry. I think I missed some and quite a few died in the trap. I think I will try to get them to lay on a removable substrate next brood.

I transferred them to un-tinted water directly from the parent tank that I filtered through a 100 micron sock into the fry tank. I ensured the temperature was perfectly matched to the parent tank before transferring the larvae. I then started a slow drip (less than 1 drip per second) of 500 mL of parent tank water tinted with 5 mL of RG complete. The next morning I added a 1 gallon harvest of rotifers that I strained and rinsed with parent tank water. Yesterday afternoon I started another drip of RG complete tinted water, this time diluted about 1/2 with RODI to account for evaporation of the fry tank water, trying to maintain stable salinity. I also added a second 1 gallon harvest of rotifers to get the fry tank density up to about 10 rotifers per mL. This morning I started a new drip of RG complete tinted water and checked the rotifer density which was still within my target range of about 10 rots per mL, so I did not add more. The larvae seem to be doing pretty well, though I think I have lost about 25% of them.

 

[Formulator]

I think I’m down to 2-3 survivors. Zero clue why. This is frustrating!

 

[MnFish1]

One issue may be that they are not getting enough live food.

 

[Formulator]

One issue may be that they are not getting enough live food.

They had plenty of live healthy rotifers. I counted them under a microscope twice/day and were always at least 10 rots per mL. I read some people don’t like to use RG complete for tinting the water. The mass die off happened after my drip of more green water yesterday. Maybe I over tinted or maybe the RG complete messed with the pH?

 

[MnFish1]

They had plenty of live healthy rotifers. I counted them under a microscope twice/day and were always at least 10 rots per mL. I read some people don’t like to use RG complete for tinting the water. The mass die off happened after my drip of more green water yesterday. Maybe I over tinted or maybe the RG complete messed with the pH?

It might have been the RG. I might avoid that except in the tank you're raising the rotifers.

 

[Formulator]

It might have been the RG. I might avoid that except in the tank you're raising the rotifers.

What do you recommend for tinting the fry tank?

 

[MnFish1]

What do you recommend for tinting the fry tank?

In my experience, you can have problems with overdoing the RG. Many people use it with no problems. You can use it in your fry tank. Again - just be sure about the dosing, etc.

Have you considered putting your pair in a smaller tank - from which they could be removed on hatching day - which may be easier on the fry than transferring them?

 

[IKD]

It might have been the RG. I might avoid that except in the tank you're raising the rotifers.

I agree with this. If you use RG Complete, it’s highly concentrated and I believe killed my first couple batches because I didn’t properly dilute it before adding the fry tank.

 

[IKD]

I agree with this. If you use RG Complete, it’s highly concentrated and I believe killed my first couple batches because I didn’t properly dilute it before adding the fry tank.

Check out Rotigreen omega

 

[Uncle99]

What do you recommend for tinting the fry tank?

A rotifer itself is not a great food item but acts as a delivery device.

I gut load Rotifers with phyto and selcon for hours to enrich their nutritional worth, before I feed that “package” to fry.

Many fry perish because they get damaged in the transfer process.

Keep fry in hatching tank and move parents should provide better yield.

You can start to introduce pulverized flake at 7 days in combination with Rotifers and slowly wean to flake/pellet only.

Metamorphosis seems to kill quite a few more for me but pass this stage, numbers stay strong.

 

[MnFish1]

Additionally, check out this company - which can advise you as to which size works best for new fry. I had some luck with their fry food (I can't remember the size for newborns) - it is, though, difficult to 'make' them eat it.

 

[MnFish1]

GP 50 - 100 Micron Reef & Larval Diet

Golden Pearl 50 - 100 micron size is suitable for most filter feeders, LPS corals, marine and freshwater larval fish and fry, including weaning discus.

www.brineshrimpdirect.com

 

[Formulator]

A rotifer itself is not a great food item but acts as a delivery device.

I gut load Rotifers with phyto and selcon for hours to enrich their nutritional worth, before I feed that “package” to fry.

Many fry perish because they get damaged in the transfer process.

Keep fry in hatching tank and move parents should provide better yield.

You can start to introduce pulverized flake at 7 days in combination with Rotifers and slowly wean to flake/pellet only.

Metamorphosis seems to kill quite a few more for me but pass this stage, numbers stay strong.

Mine made it through the first night and mostly died 48 hours after hatch. The rotifers were well fed with RG complete and had full green bellies under microscope. I’m leaning toward a pH issue due to RG complete use in the fry tank, tinting too dark or improper lighting. Is there some kind of color chart for comparison to water to know how much to tint? And is there a light intensity recommendation in lux or PAR? The problem I’m finding is that all of the descriptions are pretty subjective or qualitative and I can’t seem to find a quantitative way to make sure I have it right. For example “pea soup” and “not too much light, just enough so the fry can hunt” mean absolutely nothing useful to me.

 

[Formulator]

In my experience, you can have problems with overdoing the RG. Many people use it with no problems. You can use it in your fry tank. Again - just be sure about the dosing, etc.

Have you considered putting your pair in a smaller tank - from which they could be removed on hatching day - which may be easier on the fry than transferring them?

I probably overdid the RG complete. I don’t want to move the pair from my main reef tank display. I’m just not that vested in breeding them consistently. I just thought it would be fun to try once or twice to prove to myself I can do it and because my daughter would love it. I am going to try again and I may attach a tile to the rock where they usually lay eggs so I can remove it before hatch and avoid using the trap.

 

[Uncle99]

Is it possible that Rotifers were in the water, but not active and the fry ignored?

Can you tell if any actually took the Rotifers?

48 hour death may indicate starvation.

I drip Rotifers and Phyto mix all day.

 

[Formulator]

Is it possible that Rotifers were in the water, but not active and the fry ignored?

Can you tell if any actually took the Rotifers?

48 hour death may indicate starvation.

I drip Rotifers and Phyto mix all day.

How can you tell if the fry are taking the rotifers? I still haven’t cleaned the tank out so I could stick a dead fry under the microscope if I know what I’m looking for.

 

[Uncle99]

I use a 10x magnifying glass.
They should be “darting” in the water column.
I can’t see the actual consumption, just the movement.
It’s easier when you have a couple hundred.

Light is dim and not direct.

 

[Formulator]

I use a 10x magnifying glass.
They should be “darting” in the water column.
I can’t see the actual consumption, just the movement.

Thanks. I wonder if I can do some kind of post-mortem autopsy under the microscope to see if the dead fry bellies are green or empty… I might take a look just for fun