Some thing weird happened to my catfish...

[Catkramer]

I woke up this morning to find this little guy floating in my plants. He was the active one of the two upside down catfish, the other one hides ALOT and I actually had to go in and move things around to find him.

I am not sure what happened to him, but he has this strange HUGE yellow spot on his back, and I am wondering if he got stuck by the heater or something. He may have already been dead when it happened. Or maybe this is an illness. I am not sure. I am taking him back today to get a new one, as I have only had him for about 6 days.

No other fish look sick. Still have atleast 4 to 7 fry swimming around. My golden female molly looks pregnant as she is getting REALLY fat.

I tested my water, the nitrites and nitrates were good, no chlorine, and my amonia is right at .25 still. I haven't done a water change in a few days, and wondering now if I need to.

Here is a pic:

Any ideas what happened to this guy?

Cat

 

[Egress]

I'd agree that a heater burn would be a good explanation, and that there probably isn't any way you can know now whether that was the problem or a symptom. As you add more occupants to your 55G you may want to consider setting up some quarantine equipment. Any time is a good time for a water change!