Potentially Sick Convicts
Have some odd behavior low appetite on two out of 4 convicts in well established tank. 15 year fish keeper, never had a death! and don't want any. But a bit unsure of what might be going on.
Have 4 juvenile convicts since APR in 37 unplanted tall tank. Water parameters are historically good with pH 7, amm, nitrites 0, nitrates between 5-10. Temp 70. Do weekly pwcs. Fish usually active, doing the dance in the corner when I walk by or they are hungry. Same pattern week after week since APR. 2 weeks back, after my wife mentioned they were "skittish", I checked the water and found that the pH had dipped (6.4) and nitrates were up to 20 which is unusual (amm, nitrites still 0) and learned she had been feeding them some pellets instead of omega one flakes I had been feeding them. That was stopped 2 weeks back returning to the flakes. I think some of the pellets were going uneaten and polluting the tank a bit. They would "swell". As mentioned, this food was stopped 2 weeks back.
PCW done two weeks in row, water is back to normal patter of a 7,0,0, <10 with a 3ppm rise per week in nitrates. Right now parameters 7,0,0, 5. But 2 of the fish do not seem to be eating much, and they seem jumpy racing round the tank if you go near. No visible disease symptoms, no new fish, substrate, plants etc. Just the PWCs. They have never liked these but get over it, an hour after I am done. The only thing my wife mentioned is that one of the fish, the fin wasn't as smooth as it had been and is more "spiny", but not seeing anything like I read of fin rot. They also seem more sensitive to the light now. More calm in dimmer tank. Fish are about 2-2.5", all male. Colors/markings seem normal. They seem to change depending on time of day, and mood from mostly black spots/short stripes to very prominent black stripes. They have always been decent tank mates with one claiming a cave, the others various plants. But no aggression usually swim together except for the cave dweller.