I have a 5 year old female jack dempsey about 5inches big that is looking sick/depressed. This is an ongoing situation which has been occuring for about 2 years. She is extremely lethargic and sits on the floor of the tank all day. Gill movement is very slight and you need to get close to see if she's even still alive. Usually her tail is clamped. There's nothing obviously wrong with her and the fish looks otherwise healthy (no lesions etc.). She isn't really interested much in food and is not eating a great deal, unless I feed frozen bloodworms in which case she'll speed out to get them before any other fish does. I don't want to keep feeding just bloodworms because I'll never get her back on pellet food. I have tried not feeding for a few days etc to tempt her to eat but to no avail, she still eats minimally. I have occasionally seen her trying to flash/scratch up against rocks but can't see anything on her body so not sure what else could be causing this. I did have one fish with internal parasites and treated all the fish in the tank with metronidazole in food about a year ago. I was hoping this would also fix up jack dempsey (who was developing a case of HITH at the time which is fixed now) if she had an internal parasite. I'm not sure what colour the Jack dempseys poo is because she rarely eats and mostly hides. I'm not sure if this is relevant but when I put her in the current tank about 2 years ago she laid eggs for the first time, but has never done that again (I'm not sure if this could be because she's become sick or if I just somehow managed to have egg-laying conditions at the time). From memory she was more active back then. If anyone has any ideas about what could be wrong with her I would love to hear your opinions. Tank is freshwater 400L (100gal), lightly planted, 2yrs old. There are also some fake silk plants (azoo 'real plant' brand) which are a recent addition. I am using a canister filter that does about 150L/hr from memory. The tank is quite deep (2ft), and I have no airstone, so I am not sure if it could be an oxygen issue that is affecting the fish? I've got lights on the tank for about 9 hours a day. Tank mates are 2 bristlenose catfish and 1 geo brasiliensis of similar size. Jack dempsey is the dominant one and 'owns' the tank so to speak, but otherwise they all get on quite well. ammonia, nitrite - 0ppm; nitrate - 5ppm. (API testkit) pH - 7.4 temp - 29 deg C