I posted in another thread about a group of severum that I rescued. However they do a lot of hiding and are showing no color. I was wondering what I should put in for dither fish since all 6 of the sevs are around 6". I want to do roseline sharks but I can find them large enough to not be food. Other fish in the tank are 3 silver dollar, 2 geophagus, and 5 acara.