I kept a pair of occelaris clowns with my anemones for years without any real concerted effort to raise the fry. When Covid 19 struck and it seemed like we’d be housebound for the duration, I decided to step up my efforts.
The adults were considerate enough to always spawn on a removable potsherd, so I set up a 17 gallon tub with central aeration and moved he eggs into the tub. In tandem, I set up a ‘compact culture system‘ from Reed Mariculture with rotifers and algae paste.
Then followed a long series of failures. The fish spawned regularly, but my rotifer cultures almost always crashed, pretty much always immediately before the clownfish eggs hatched. I spent a huge amount of money with Reed, ordering bag after bag of rotifers but somehow never managed to have both a live rotifer culture and clownfish fry at the same time. At one point I arranged a no-contact handoff of live rotifers from Chad Vossen in order to collect rotifers on the day of hatching but I still never got the fry properly fed.
I raised a very small number of fish on brine shrimp only, without rotifers, but the results were very disappointing.
Meanwhile, I was also trying to raise amphidromous pipefish, and had a 2.5 gallon tank full of low-salinity brackish water and rotifers for pipefish food. I never got the pipefish fry to eat the rotifers, but I did discover that the rotifers were thriving in their brackish tank, despite always dying off on the ‘culture system’ bucket.
So, the breakthrough was abandoning the bucket, and also abandoning the algae paste. I got a nice co-culture of live phytoplankton and rotifers going in the black tub, and added the fry. Then: hands off, no additional food for the rotifers and no additional rotifers in the tub. That worked pretty well! Finally I was able to get a large number of clownfish fry to settle.
Once the fry were large enough (both before and after settling) I supplemented their food with selco-enriched bbs. After settling I started feeding them dry TDO food, and added a little air-driven protein skimmer to the tub.
In retrospect, raising these fish was not very complicated once I was able to keep rotifers alive.
