i have a RTC and he about 5-6inch i got him about 2-3 weeks ago and he was about 3-4inch. he growing really fast healthy and active he even swim around the tank when the lights are on, during the day time and specially when it's feeding time. he have no problem taking food from my hand. i also have a few other fish in there and a jardini. my jardini got a little scratch and a little rip fin maybe from a fight with other fish. i added a little aquarium salt in there about close to 1 tea spoon. i don't want to add a lot because im not sure about my catfish. i don't want to take my other fishes out because a 2 of the other fish and my jardini have a rip fins so i want to heal all of them and i dont have room of each of them when i take them out. my tank is a little longer than 6ft length and 2ft width but im going to say 6x2x2 so about 120 gallons. will my catfish be fine with the aquarium salt?