I would only do a single ram alone for a 10g, if I did one at all. Bumblebee gobies could work well, though most say you they need to be in low-end brackish water, even though they do breed in freshwater. You could probably convert your tank to brackish without too much difficulty, though, as most livebearers are tolerant of brackish and even saltwater for Poecillia species. They also require small live or frozen foods.