I dont mean this to be rude or mean in any way at all, but sI was going to buy one of those and someone on here made me decide different. He referred to them as being as hardy as a full blown AIDS victim. It is most likely not from something you did but just the nature of the fish itself. Someday this will change just like before when noone thought you could ever keep a mandarin Goby in a closed system, but most do fine now in established tanks. Good luck with your ray, I have a similar issue with a gar I just cant seem to kill. He hasnt eaten in over a month now and is still breahing fine but cant swim worth a sh*t. Good luck to you and your ray.
