The Golden Harlequin Rasbora is one of the most popular aquarium fish due to both their coloration and temperament. These fish have a black triangle-shaped patch starting near the dorsal fin, and the body has a golden hue. The male's patch is slightly rounded at the bottom with an extended tip while the female's is straight. Females are larger than the males.
Harlequins require an established planted aquarium of 10 gallons or more. They should be kept in schools of 8-10 and in an aquarium with other small, peaceful fish.
Rasbora heteromorpha generally spawn on the undersides of broad-leaved plants. A breeding tank with shallow, warm, acidic, soft water with broad-leaved plants should be set up. Keeping a pair of young females (9-12 months old) with a two-year old male along with feeding them live foods will greatly improve the chances of spawning. After spawning, remove the parents and keep the aquarium dark until the eggs hatch (after about 24 hours). Feed the fry infusoria.
An omnivore, Harlequin Rasboras do well on a diet of prepared flake food, as well as freeze-dried bloodworms and tubifex.