Hi I am goin g to use my 90g to grow out a red parrot, king kong parrot, FH parrot, two oscars, green terror, and red high fin wolf fish. Right now they are all about 3 to 4.5 inches long. Should I put in gravel/sand and decor for hidding spots? My fear is that if I have decor in the tank they might become territorial. What are peoples experiences? Thanks