Least Rasbora

The least rasbora (Boraras urophthalmoides), also commonly known as the exclamation point rasbora, is a tiny, peaceful schooling fish perfect for nano tanks and planted aquariums. Their slender bodies feature a dark horizontal marking ending in a distinct spot near the tail, giving them their “exclamation point” nickname.

Least rasboras earn their name by staying small, so they are great for aquariums with small shrimp. Growing to only around 3/4 inch, least rasboras are true micro fish and look their best when kept in a school of at least six. Larger groups will generally be more confident and display more natural schooling behavior. Their peaceful temperament also makes them excellent tank mates for fancy shrimp and other small, gentle species.

Quick Facts

Care Guide

Tank setup: Give them dense plants, floating plants, a dark substrate and gentle filtration (a sponge filter is ideal, since they are small enough to be pulled into strong intakes). Soft, slightly acidic water brings out their best color.

Feeding: Feed crushed flake or micro pellets once or twice a day, only as much as they eat in a couple of minutes. They also enjoy frozen brine shrimp.

Tankmates: Keep them with other tiny, peaceful fish such as other micro rasboras, small tetras, pygmy corydoras, otocinclus and dwarf shrimp. Avoid large or boisterous fish, which can eat or stress them.

Good to know: Micro rasboras show their best color and natural schooling behavior in larger groups and well-planted tanks.