How many inverts are to much. I currently have a 12g dx nano cube with 4 bumble bee snail, 2 fighting conchs, 2 dwarf zebra crabs, 2 dwarf red tip crabs, 1 electric blue leg, and 1 dwarf blue leg. Could I add more or is this enough. I would like to add 1 more electric blue leg, and 1 more dwarf...