I need advice on my fish tank, please any advice is appreciated.?

keeping that fish alive will costs u loads of money i think its time to let him go the fish is very ill and its sad to keep him alive he could be in pain if he does die treat ur tank and disinfect it all ur otherfish should be fine im sorry about the one tho ask me if theres any other signs if there is a black spot where they have babies from ur fish might be dyingcause of its babies it happens