My niger catfish and irwini catfish are not getting enough food in my tank. They are not growing as fast as they should be. This is b/c they hide all the time together in a cave. I can't take the cave away though b/c then my parrot fish that I have in the tank will have no place to hid when they need to. I was thinking of putting these two catfish in my bare bottom,plain tigrinus catfish growout tank. The tig catfish is around 4.5" which is the same size as the irwini. The niger is about 6-6.5". Will they fight if I put them together? Will the irwini and niger feel insecure in an open tank? The tank is 27g. It would only be until I fatten them up a bit. Will it work?