You have alot of options to go with here. Do you really want Guppies? Yes, they are pretty but they are live bearers and breed ALOT. Of course, I don't know if they will all fight if they are just females, or just males. I would recommend getting TWO bottom feeders. They do VERY well in groups, and enjoy company. For example, my two Cories in my sig. I also have a Pleco but her isn't in there. Cories would eat alot of the food the other fish don't eat, etc. If you're looking for an algae eater got for a common pleco. Obviously, the small species.