Aggressive towards conspecifics and possibly other similar looking fish but otherwise peaceful. If more than one is being kept then provide them with lots of hiding places and visual barriers in order to minimise fighting. Sumo loaches come from fast flowing, clean highly oxygenated water and this should be replicated in the aquarium to some degree, good movement (don't over do this by making rapids like conditions in the tank, good movement is all that is needed) of clean highly oxygenated water will help these fish to thrive.
Feeding Sumo loaches are relatively unfussy about their food and will accept most things offered with out any problems. A mixture of a good quality dried food such as flake, granules or suitably sized pellets supplemented with live or frozen daphnia, cyclops, mosquito larva, adult brine shrimps or blood worms will make a fine diet for these fish.
Compatibility Danios, rasboras, tetras and barbs all make good tank mates. Avoid large or more aggressive species and other loaches.