unfortunately I found out about the size oven iridescent shark after I got him as for what else I have in the tank 7 tiger barbs a pleco not sure what type and a red tail sharkWhat other fish do you have with it? I'd guess he had his whisker bitten.
Just so you know, iridescent sharks will get well over a foot long and need a few hundred gallons when they are adults.
I was trying to play it safe and have raised the temperature of the water to about 84 degrees I was going to add just a little bit of salt what do you thinkit's most likely a bruise from the fish getting caught on something and damaging it a bit. Monitor it over the next few days and if it goes white and fluffy (fungus), then add some Methylene blue to treat it. But if it doesn't get worse don't bother treating it.
I heard that plecos may have a hard time with the salt is that truea bit of salt should be fine. you don't have to raise the temperature.
unfortunately I found out about the size oven iridescent shark after I got him as for what else I have in the tank 7 tiger barbs a pleco not sure what type and a red tail shark