Maximum size : 2 cm

Exclamation Point Rasbora - Boraras urophthalmoides : Complete Fish Profile & Care Guide

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The Exclamation Point Rasbora (Boraras urophthalmoides) is a fascinating species that deserves a place in any aquarium enthusiast's collection. Although small and timid, it is a hardy and peaceful fish that makes an ideal companion for other miniature species or shy anabantoids. In fact, it's perfect for the nano or planted aquarium.

This Rasbora is a shoaling fish that thrives in groups of 8 to 10 specimens. Not only will a group make the fish less apprehensive, but it will also result in a more impressive and natural-looking display. As males compete for female attention, they will present their best colours and show some exciting behaviours.

A well-maintained aquarium environment is crucial for the health and well-being of Exclamation Point Rasboras. To create suitable habitat, the aquarium should be fully matured with a diverse range of hiding places provided by driftwood and lush vegetation. Floating plant species can be added to help regulate light diffusion and create a more natural-looking habitat. Filtration is also essential, but water movement should be gentle, as these fish naturally inhabit slow-moving waters. Maintaining proper water quality and circulation is critical to ensure the Spice Rasbora remains healthy and disease-free.

The body of Exclamation Point Rasboras is typically golden yellow with a dark green or brown lateral stripe running down both sides of the body, ending just behind the dorsal fin. When in good condition, some populations develop an intense orangey-red line above the dark lateral stripe, adding to its beauty. What sets this Rasbora apart from others is the distinct round dark blotch on the caudal peduncle, resembling a horizontal exclamation mark. This unique and eye-catching feature makes it a true standout in any aquarium.

Exclamation Point Rasbora Photos

Sexual Dimorphism

A clear distinction between male and female Exclamation Point Rasboras can be made based on visible physical characteristics. Female Rasboras usually exhibit a larger body size and a more rounded abdomen, while males tend to be slimmer. During the breeding season, males display a reddish hue, and females have a golden colouration. These gender-specific features allow for easy identification of this species, which can be useful for breeding programs or simply for distinguishing between male and female individuals in a community tank.

Quick Facts

Scientific NameBoraras urophthalmoides
Year Described1991
Other NamesLeast Rasbora, Sparrow Rasbora, Spice Rasbora
OriginsThailand , Cambodia , Vietnam
Max Size2 cm
Aquarium LevelMiddle - Top
DifficultyBeginner - Intermediate
Best kept asGroups 6+
Diet & FeedingOmnivore
LifespanUp to 5 Years

Water Parameters

Water TypeFreshwater
pH 6.0 - 7.0
GH 8 - 12
TDS 18 - 179
Ideal Temperature
76 - 82
24 - 27

Natural Habitat

The Exclamation Point Rasbora can be found in the southern peninsular of Thailand in the Sai Buri, Mae Klong, and Chao Phraya River Basins. These captivating fish inhabit shallow water structures such as marshes, swamps, ponds, rice paddies, and peat bogs, where they are surrounded by lush aquatic vegetation that creates a serene and picturesque environment. 

The water in their natural habitat is typically soft and acidic, sometimes tinted with a tea-like colour from tannins. But the allure of the Exclamation Point Rasbora extends beyond the borders of Thailand; this remarkable species has also been spotted in Cambodia and Vietnam. In an unusual twist, a group of these fish have even taken up residence in the moats and ponds of the iconic Angkor Wat temple complex near Siem Reap. 


Raising Exclamation Point Rasboras requires a careful and controlled approach. As a species of egg-scattering, non-stop spawners, they exhibit zero parental care, similar to many Rasboras. However, if you wish to increase the number of fry, a separate breeding tank should be set up with the right conditions. The breeding tank should have slightly acidic water and be dimly lit, with a bottom either bare or covered with mesh to allow eggs to pass through. Fine-leaved plants such as Java moss should be placed in the tank, taking up about half the available space. Filtration is not necessary, but a small, air-powered sponge filter can be used.

After conditioning, two or three pairs of well-conditioned adult fish should be slowly introduced to the breeding tank to avoid extreme stress. If conditions are to their liking, the fish will begin spawning the following morning, with daily spawning continuing. Pairs should be removed after a couple of days as the first eggs will start to hatch by the second day after the original spawning.

The tiny fry will survive on their yolk sacs for about 24 hours before requiring infusoria, paramecium, or other microscopic food. After about a week, they will be big enough to accept foods such as nauplii, artemia, and microworm. Additional babies will start to appear from later spawning results. Performing small water changes should be delayed for a week or two to avoid unnecessarily shocking the young fry. With the right conditions and approach, Exclamation Point Rasboras can thrive and produce healthy fry.

Diet & feeding

In the aquarium, Exclamation Point Rasboras will readily accept dried foods of appropriate size, such as micropellets and crushed flake food, but a varied diet is essential for optimal health. Offering small, live, and frozen foods like baby brine shrimp, daphnia, cyclops, and mini bloodworms daily will not only enhance their vibrant colors but also stimulate breeding behavior.

Other Rasboras of interest