Yes, i think it was lack of food. I did finally get an algae bloom started in a 300 gallon ibc but it was too late. I can also see the tiny zooplankton swimming around so i think it would have been sufficient if i had it a week earlier.
Not enough food at the right time soon after the hatching of yoy is also a big killer in natural outside waters. It is often noted in studies.
It also happens to those of us that produce yellow perch in ponds in early spring. It's tough to get an algae bloom going to feed the zooplankton in cold water, and if you get a cold snap things can go awry.
Additionally as Bill Cody will tell you, not only do you need the zooplankton there at the right time, you also need the right sizes for the mouth gape.
