John Kruid, do you know what caused the fish kill? Other than adding aeration last year, how has the pond changed since the fish kill 4 years ago?

Yes, not all fish float when they die. More float in summer months than when the water is cold. With the LMB in there, the YP are good prey for them, so even without a fish kill, periodic restocking is recommended, especially if you do not have the correct cover in the pond to facilitate high a high number of YP eggs to hatch when YP spawn. What cover do you have in the pond to help YP spawning success?

www.hoosierpondpros.com

[Linked Image from lh6.ggpht.com]
http://www.pondboss.com/subscribe.asp?c=4
3/4 to 1 1/4 ac pond LMB, SMB, PS, BG, RES, CC, YP, Bardello BG, (RBT & Blue Tilapia - seasonal).