Swimming problems, genetic?
About a year ago I adopted a Notropsis chosomus (rainbow shiner) with a genetic malformation. Born with a bent fin. Although slower and smaller than his mates he always seemed happy and healthy. 2 days ago he started having swimming problems. Can't stay straight or looks like he needs to use a lot of energy. Water conditions including NO and NH4 are fine. I have a fully cycled canister filter so I would say it's not ammonium poisoning. Only problem is the heat wave and the temperature has been 25 C for a couple of weeks. Just moved him in a 60l hospital tank because I saw the others picking on him. Any advice? If it's genetic nothing i can do about it but i am wondering if i am missing any other possible cause. Sorry for the long message.