Glad I found this site/forum, hope I am not too late. I have a 12yo pond, 1/5 acre, 7.5 feet deep, sealed w bentonite. Pond contains CC, LB, BG, Crappie, and Talapia. I have spent several hours going thru this forum and found that I have been severely neglecting my pond for years. I have never had an issue until now. I noticed 1 dead CC 7 days ago. First one ever so I wasn't too concerned. Last night I found another dead CC and crappie. Now I know I have problem and im trying to act quick to avert disaster. After reading numerous posts on this site I am aware that I may have several issues, first one I believe I need to address is aeration (chemical kill is not possible). I have the diffusers and weighted line covered, trying to find pump recommendations and where it can be purchased for reasonable $. I have temporarily set up my trolling motor on my dock to try and get some circulation and more oxygen in water. I have a well by pond w submersible pump, and have the ability to add fresh water, would this help or make problem worse? I have several 5lb LB that will literally eat BG out of my hand. If my ignorance causes their demise I will be sick to my stomach. Any ideas suggestions will be greatly appreciated.