iridecent shark messed up nose and tail

i just recently got an eight year old iridecent shark from my aunt and i also bout a good sized plecko. in the past few days the sharks tail on the bottom has developed a white area that looks as if it was infected or something and his nose looks as if the top layer of his skin is coming off. it doesnt look good at all and im starting to get really worried about him. my plecko also has the nose problem but it just started today and only has a very small patch of it. if anyone knows what they problem may be please let me know!

 

i've seen this before on big fish in small tanks. is that the case here? there is a disease that will do that as well although i cant recall the name of it

 

hes in a 75 gallon but i got the tank from my aunt and hes been in the same tank for years. there was about a week and a half that he was in 130 gallon but i doubt him being in the bigger tank for that short time made any difference

 

I'm sure you have heard it before but that's a small tank for iridescent shark imo
I have heard of them having problems in smaller tanks as the other poster stated.

 

i wish i could afford a bigger one. but why would it start now if hes been in the same tank for so long

 

Fish get bigger as they get older. Especially catfish of the iridescent shark type body plan (the big mouthed ones). I mean, we're talking about a fish you see at around 3 inches at Petco, but grow to 4 feet in the wild.