Harlequin Rasbora
Trigonostigma heteromorpha
Family: Cyprinidae
Harlequins are my "set it and forget it" fish. Hardy as nails, beautiful copper-orange color with that iconic black triangle. They fill the middle of the tank perfectly and school loosely without the neurotic tightness of some tetras.
Water Parameters
Temperature
pH Level
Hardness (dGH)
Care Tips
Probably the most beginner-proof schooling fish. Survived my learning mistakes including a heater malfunction that dropped temp to 65°F overnight. Keep 6-10 for natural schooling behavior.
Feeding
Zero problems here. They eat everything I offer—flakes, pellets, frozen, live. Not picky at all. I feed once in morning, once at night.
Breeding
Unusual breeding—they lay eggs upside down on the undersides of broad leaves like Anubias. Soft, acidic water helps trigger spawning but I've never tried breeding them deliberately.
📚 Sources: Care parameters based on SeriouslyFish, FishBase, and Aquarium Co-Op. Personal observations from the author's 5+ years of fishkeeping experience.