Tank is a 125g, all male Haps and Peacocks tank. I have about 23 or so fish in the tank now. Has been cycled and operating for about 7 months now. This fish is about 4 inches in length. Red spots on fins only. Has been acting a bit shy lately.
Running two sunsun 3000 canister filters. Water parameters are 0 ammonia and nitrites. 8.0 ph. Nitrates are 40-80 ppm (trying to get this down). Kh around 9 and Gh around 11. Clean weekly with about a 70% water change.
Yes he is getting attacked...see the shredded fins? The red spots are even more concerning, usually not a result of aggression alone. The only time I have seen red spots it is septicemia (blood poisoning) which is a fairly advanced symptom of many diseases.
I would isolate the fish in a hospital tank with nitrates below the 40-80 in your main tank. Then reduce the nitrates gradually by changing 50% daily.
In the main tank, are the filters and substrate clean? I would change 50% 2X daily until nitrates are under 20ppm.
He is also fat so try feeding less. This will also help reduce your nitrates.