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How to Care for a Harlequin Rasbora

The harlequin rasbora is a popular fish among aquarium enthusiasts because it is easy to care for and is a peaceful fish that does well in a community tank. It will grow no larger than 2 inches. It is often confused with the lambchop rasbora and the glowlight rasbora. A harlequin rasbora can range from light pink to red in color. It has a bluish-black triangle-shaped mark near the back fin.


A tank of no fewer than 20 gallons is required for harlequin rasboras, but larger is preferable. A good rule of thumb is to have 2 gallons of water per harlequin rasbora. They require a large open area to swim in but also need dense plants in the back and on the sides of the tank to provide hiding places. The harlequin rasbora is adaptable to most water conditions, although pH below 7.5 is best. The optimal water temperature is between 73 to 82 degrees. Normal aquarium lights are sufficient for the harlequin rasbora, no special lights are required.


A quality tropical fish flake food is sufficient for daily feeding. To maintain a harlequin rasbora's coloring, supplement with live or freeze dried worms and brine shrimp several times a week. Feed a school of rasboras three times a day, only as much as they will eat completely with in three minutes.


A harlequin rasbora does not breed easily in captivity and needs special conditions. The water level needs to be lowered to about 8 inches and the lighting reduced to very dim lights or no lighting at all. The water pH will need to be more acidic and should be lowered to below 6.0. Fake or live aquarium plants for eggs to adhere too are necessary. Once you see eggs in the tank, remove the parents and reduce the water level 2 more inches. Make sure the eggs are underwater at all times. They will hatch within 24 hours.

Suitable Tank Mates

The harlequin rasbora is a peaceful, nonaggressive fish that should be kept only with other small, peaceful fish. Fish such as tetras and guppies are also peaceful and small, making them good tank mates for the harlequin rasbora. Other suitable tank mates include the pitbull pleco, the cherry barb and the dwarf gourami -- they are all peaceful fish.