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I've had my Catfish for a little over 4 years now and it's always had a growth that would come and next to its top fin. It grows and fills with blood pops, then heals and repeats. It doesn't seem to both the fish much. curious it his is common and if anyone can tell me what is? He is about 13" long and weighs about 2 pounds. Has Jumped out of my tank twice, but survived both falls. Tuff fish! Thanks!

Picture of the wart thing:


Full picture of my Catfish

Maybe something in the water is stopping the wound from completely healing? It sort of heals but then is reinfected before it is completely better. How big is the 'wart'?
Or maybe I'm completly wrong? I'm sure other people have a lot more experience than me.
Edit: I almost forgot - very nice fish!