I'm pretty new at this and have a question about my black skirt tetras. I have 3 of them and all of them just hang out at the bottom of the tank. When I feed them they won't go to the top to feed, they wait till the flakes fall down in front of them, then they snag them. When I turn the lights off they will swim a few inches higher but still mostly stick to the bottom. My questions are: 1 - Is sticking to the bottom normal? I have two red claw crabs, hoping they would "push" the BSTs up, but that hasn't happened. Also would getting some top swimmers help? 2 - How can I get them to eat at the top? The set up: -Started the tank Nov, 7. -Added 3 BSTs Nov, 9 after running the tank over the weekend. -Added 2 Red Claw Crabs Nov 24. -GH 0, KH 240, pH 7.5, NO2 0, NO3 0-10 ppm -Ammonia not sure - had the water tested around the 18th and the guy said there was a little but a normal amount for a new tank. -Temp 75 -Not sure what watts the lights are. They are 2 incandescent bulbs that come in the top fin 15 gal starter kit. This is a picture of my tank. I've heard that I need enough plants for them to feel comfortable. Is this an ok amount? Usually at least one of these guys is hiding so this is an unusual photo of all of them in the open. This is the level they typically hang out at. When the lights are off they will swim 2-3 inches higher.