Most people generally will say dont buy a fish if it looks sick or is beat up, but if you like it and want it go for it. I bought a female fh that had major damage to all fins and side of body, but she is recovering pretty quick. In about 3 weeks she grew almost all of her fins back, beside the tail thats taking longer to come in but getting thier. They are hardy and recover quickly , imo... Also if you have big enough tank you might be able to work it out with tank mates but all 4 of my fh are seperated and by them selfs..... My small 2 inch ZZ killed my green terror and a pacu i had in the tank so i kkep um seperated. They are def. Aggresive fish.... Also i am no expert and dont no a hole lot ,so correct me if im wrong people, but they are like any other fw fish when it comes to disease. Health issues may depend on that single fish being these are hybrids.