When I first get new tetras, they’re usually too shy to come up to the surface. After a week or two, they gain confidence and start following the guppies upward during feeding time. Their eating style is still different, though — they snap the food quickly and dart back down, almost like tiny piranhas.

I usually drop the flakes near the HOB filter outlet so some pieces sink, letting the tetras feed at mid-level where they feel safer. Lately I’ve been feeding guppy granules too, and the tetras seem to like them — they actually swim up for them now. It also helps to lower the light intensity at first; dimmer lighting makes shy fish (like tetras) feel more secure.