Evidently I didn't do a very good job of explaining it the first time.
I'll try again to explain the value of an cone shaped aquaculture tank...
When I feed train sunfish, usually pellets do one of two things--they float, or they sink. True, some sink more slowly than others, but if they don't float, they end up on the bottom. Hungry lepomids like bluegill and redear sunfish will hit the pellets off the top if there's a good enough combination of hunger and temperature, but they will sip, spit and re-sip pellets on the way down. However, once the pellet's on the bottom, they won't ever pick it up. Ever.
Therefore, the conical tank is preferred so you can offload the uneaten pellet ASAP so it doesn't start to degrade and affect your water quality.
This would be a 2-4 times daily regimen until the sunfish have figured out the pellets so there is 100% consumption.
The other major factor is solid waste. Suspended wastes will be eliminated by filtering, biofiltering, and water replacement, but solid wastes will settle to the bottom, and can be easily removed with a cone-botomed tank. That's why it's an aquaculture standard. Usually these things are so labor intensive that you need quick ways to treat water.
Holding a redear sunfish is like running with scissors.
