My old peppered cory recently died. He went white on his stomach and spent a lot of time in the last couple of months with his head at the surface of the tank. At times he appeared to be sleeping deeply. he did eat small amounts of food in his last few days but gradually got thin. My 2 cories that are left have also developed white bellies. I bought them about 3 -4 years ago when they were fairly small. They were 'home bred' but sold in a lfs chain. They started out looking like bronze cories but now both have only a bronze stripe down the center longways of the body. One looks a bit thin to me. I don't know too much about these guys as to what to expect as they age. There have been no new inhabitants to the tank in the past 6 months. tank mates are 1 full grown SAe, 2 emperor tetras, 6 platies, 1 kuhli loach, 1 baby albino plec. Tank is planted and has been set up for about 10-11 years. water changes are done q 2 weeks. No ammonia or nitrite, 5 nitrate. Water is hard, ph 8 or so.
Tank is fed flakes every morning with 3 shrimp pellets for the bottom feeders. occasional cucumber is given for the baby BN plec.
Any ideas as to why these guys are turning white? I don't think they are that old but perhaps they have aged quicker because of being out of their water specs.