Aggressive Red Tailed Shark

Question
Hello, I have 2 Red Tailed sharks along with some tetras and a couple of fish with longer tails that were given to me . The smaller of the two sharks has become aggressive and started attacking the tail and fins of the other fish. Is there anything I'm doing wrong or anything I can do to stop it?

Answer
In my opinion, red tailed sharks should not be sold to anyone, unless tehy can provide for them. RTS are VERY agressive, expecially towards the same species and longer finned fish. Get rid of them. You cannont provide what they need. They need 55 for one and 75 for two, because they are EXTREMELY territorial.