If you could give us dimensions of the tank, it would make it easier to decide if a bottom feeder would fit. If you tank, is long and short, then I say yes, 2-3 pygmy cories, or a kuhli laoch would do quite nicely, if your tank is tall and thin, then no.I would also say, skip the zebra danios, as they could end up nipping at the fins of your tetras. The neons probably wouldn't fair well, in such a full tank.