Will 4 damsels (3 4-stripes, 1 blue velvet) be OK in a 20G aquarium? I am starting to add corals on my old fowlr, but the damsels are picking them off. the blue velvet shreded the edge of a chalice and the 4-stripes are picking on the toadstool and duncan. I don't want to get rid of them, since I have them for more than 5 years but I don't think I can have a successfull reef with them in there. So I have been cycling this 20 high, the 2 HOB filters have been running on my sump for a week and I also moved a few pieces of rock from the DT, initial water is also from the DT. Is this big enough for them?