Today was a real bummer.
I woke up to the larvae just under the surface with rapid respiration and hanging in the water column, not hunting.
I pulled them all out and put them in the holding tank. Dumped the larval tank and cleaned it. By then there were 20 dead and 30 still alive. I put the live larvae back into the larval tank with new food and headed to Waikiki to get more water. When I got home there were only 2 survivors left.
I wondered if an external parasite had been introduced with the wild plankton but could not find any evidence of that. I treated the remaining two larvae with antibiotics in an effort to learn something. Tonight I can only see one live larva left. How can one larva survive when 49 died today?
I wasn't expecting this but that is the nature of the beast. The good news is that I learned a lot from this larval run. I've also got the cultured feeds in good shape so we should have a quick turn around time.
Here is a photo to show the size of the larvae at day 24. The average body size was 4.5 mm and total length was 6 mm (the tail is clear and difficult to see in the photo).
Here is a close up of the scales starting to form. those arrow like points in between the black dots on the skin of the larva are the beginnings of scales.
Note also the dark pigmented line running through the dorsal fin. That indicates the larvae are close to settlement. (Which makes this loss even more of a bummer!)
Please keep your fingers crossed for more fertile eggs!