My Colombians with Serpaes, Bleeding Hearts and Black-skirt Tetras.
Colombian tetras are just a great all-around fish. I bought 5 last year. No deaths, no diseases, they cause no problems with other fish or each other.
These fish are not gaudy, they can look quite plain one moment, then go under the lights just the right way and look so pretty. I have seen photos of them in large groups , in a school of 20 or more, and they are impressive. A planted tank at 75 degrees F and clean water means happy fish.
Most information on the Internet calls them Colombian Tetras, but I see them at Petsmart being sold as Red-Blue Tetras. These fish are over-looked at the pet store because they look mostly silver, but I promise they will show great colors in the home aquarium.
Get some! At LEAST THREE. More if you can.
A Practical Fishkeeping Blog 