So I am planning on buying my first freshwater ray. I will probably get a motoro, as I can't really afford to pay over $100 for the fish. I have a 90 gallon tank with a fine sand bottom for it when it's small, but when it's larger I have a 180 gallon bare bottom that it can go in. Do angelfish make good tankmates? What about african butterflyfish and bleeding heart tetras?