PMD--perinatal massive death in clownfish

[jamie1210]

I am on my 3rd attempt at hatching/rearing true percula clownfish larvae. Each time, I'm making more progress! My hatch % is decent. However, the next morning, almost all of them die. Right now, I have about 12 survivors, and they are 1 day old. (The first few times I attempted this I had no survivors!) I keep seeing discussion of PMD--perinatal massive death in clownfish larvae, which describes what I'm experiencing. Seems like there isn't any conclusive theories as to what causes this. Has anyone experienced this and care to share?

Thank you!

Jamie

 

[ichthyogeek]

What are you filling the growout tank with? Fresh seawater? Water from the parent’s tank?
How are ammonia tests?
What holding container are you using?
What are you feeding, what density, and when are you feeding to the larvae?
What is the parent’s diet like?

 

[jamie1210]

Growout tank is water from the parent's tank (main tank)
Ammonia--Good point. I didn't think ammonia levels will cause all those deaths in less than 12 hours! But good to cover all bases. I will pick up an ammonia badge.
Holding container--not sure what you're asking, but my set up is this:

Move eggs on tile to half filled 10 gallon tank (so 5 gallons total) with DT water.

larvae diet: (plan on!) feeding rotifers the next morning, but they're usually all dead except for a couple of survivors! What's causing the death??

Parent's diet--Spectrum pellets, Ocean Nutrition flakes, freeze dried mysis/krill/plankton, frozen food once a week. They've been spawning for years.

What are you filling the growout tank with? Fresh seawater? Water from the parent’s tank?
How are ammonia tests?
What holding container are you using?
What are you feeding, what density, and when are you feeding to the larvae?
What is the parent’s diet like?

 

[Fishnut]

Search the tube for videos on breeding clowns.

 

[ichthyogeek]

Hmmm....my feeling is that it might be a nutrition issue. Either the larvae aren't able to ingest enough food by 12 hours to compensate for hatching/growing and starve, OR the eggs laid by the female don't have enough energy in them, and the resulting fry just don't have the energy to stay alive. One alternative is that one or both of the parents has bad reproductive genes that are causing the larval mortality.

How strong is the water/air flow in the growout tank?

Have you tried adding rotifers on hatch night as well as live phytoplankton (something like nannochloropsis)? Just so that they can jump start the feeding process?

Or have you tried adding extra lipids to the adult's diet? Something like grated squid?

 

[ThRoewer]

Do you have a film on the water surface in the larvae tank? That might prevent them from breaking the surface to fill their swimbladders.

 

[jamie1210]

The clowns are WC. I've had them since 2007! Perhaps age is a factor by now?

When the eggs are hatching I have a small airstone going enough to sway the eggs. When they hatch, I dial it down a lot so that there is movement but not overwhelming. This got me a few survivors.

I don't believe there's any sort of film on the surface. I will have to look closely next week when they spawn again.

One thing I just realized: temperature. The whole time I thought the tank was at 80, but it turned out it was at 76. Hopefully this could be the big realization. I'll keep you guys posted on next week's hatch.

I appreciate the tips!

 

[Moxtrain]

Do you have a film on the water surface in the larvae tank? That might prevent them from breaking the surface to fill their swimbladders.

Are clownfish physostomes? I kinda always assumed not.

 

[ThRoewer]

Are clownfish physostomes? I kinda always assumed not.

As larvae all fish are: "... The pneumatic duct that connects the gut and gas bladder is present in the embryos of these fish but it is lost during development. This anatomical state (the physoclistous condition) is believed to be evolutionarily derived from the ancestral physostomous state." https://en.wikipedia.org/wiki/Physoclisti

 

[Moxtrain]

As larvae all fish are: "... The pneumatic duct that connects the gut and gas bladder is present in the embryos of these fish but it is lost during development. This anatomical state (the physoclistous condition) is believed to be evolutionarily derived from the ancestral physostomous state." https://en.wikipedia.org/wiki/Physoclisti

How does that jive with fish that never get within 100m of the surface? I'm not surprised there is a connection in the embryo but is it functional or even present at hatching?

 

[ThRoewer]

How does that jive with fish that never get within 100m of the surface? I'm not surprised there is a connection in the embryo but is it functional or even present at hatching?

Which fish larvae don't get to the surface?
In any case, the larvae of reef fish do and keeping the water surface free of an oil of fat film is important during hatching.

 

[jamie1210]

Just wanted to update you guys as promised on the following hatch: success! This time, I made SURE that the temperature was 80 degrees. It is now day 2, and I still have tons of larvae. So it WAS the low temperature that killed them last time. *Fingers crossed* that they keep surviving!

 

[chaostactics]

Awesome keep us updated

 

[jamie1210]

Sadly, the update is no good.

They seemed strong and healthy up until Day 3. At the end of Day 3, I noticed some were swimming funny. They all died the next morning at Day 4. Temperature: check. Flow was good--small bubbles from airstone. Rotifers were robust. On Day 1, I added water from the parents tank (dripped in from my DT). On Day 2, I did 1 gallon water changes and dripped in water from the parent tank. On Day 3, I did another 1 gallon water change and dripped in water from parent tank. Each time, I tint w/nanochloropsis. I suspect I might have over tinted the water following the water change on Day 2? Next time around, I plan on trying NOT tinting w/nanochloropsis. I also read suggestions of bleaching the tank. What have I got to lose? might as well try that too!

Man, these guys are SO SENSITIVE! :mad:

I haven't given up! Looks like it's going to be a steep learning curve for me