if I add structure, then I will make myself get other fish. And I don't want to because this colony will be going into a smaller tank in time. Probably a 30 breeder. So I want to keep just multies, and the multies perfer shells, shells, and if you can fit in a few they would like more shells. I just don't want to tempt myself to set up another community tank when I have to use that space for something else. The 45 is really just a temp solution. I will add some structure when they go into there forever tank. Because I will then be able to build the inhabitants to the size of the tank rather then buying inhabitants that will be fine in a 45, but not in a 30 breeder. I really want some syps, but they wouldent do well in the smaller tank, so there outta the question.