This from Aqua Imports on the loach Tobias brought up:
The Royal Clown Loach or Imperial Flower Loach is the largest species of loach or botia in the world, originating in the subtropical waters of China's Yangtze River. An elongated species well adapted to life in fast-moving water, they are powerful swimmers which prefer strong current and well-oxygenated water in the aquarium. In the wild, they feed on worms, crustaceans, and other fish (including smaller loaches). They will readily hunt down and eat small tankmates so should be kept with similarly sized fish. As a cooler water species, they do best in an unheated tank with temperatures ranging from 55-74F.