Hello. I have 4 African banned barbs, 4 zebra danios, a 3 inch redtail, 2 silver tipped tetras, and 1 dwarf pleco. I have a 30 gallon tank that's in very good shape. All fish are healthy. I need advice though. My tank, though active, visually looks a tad empty. My question is, given the eventual matured size of these fish, can i afford to put more fish in?.....i wanted more middle or top swimmers to add a bit more animation to the tank. But i don't want to overcrowd my tank because i want them all to remain healthy. What do you think?