Rainbows are beautiful fish with extraordinary colors. The turquoise rainbow is a great example of the color these fish can exhibit. Growing to 3 inches roughly they are very active fish that rarely hide. They make great additions to most community tanks. Rainbows are very hardy and easy to keep. They change colors depending on how the light is hitting them. This is illustrated by the images above. Both pictures are of the same turquoise rainbow. They will eat flake foods and most other processed foods.