At a glance the quick version
Typical adults 1.2-1.6 cm; FishBase lists a maximum of 4.0 cm total length
Looks how to spot one
Miniature, slender scaled cyprinid
One of the tiniest rasboras, usually only 12-16 mm long. It has a long, unbroken dark stripe along the side and a round dark spot at the base of the tail, which together look like an exclamation mark. Depending on where the fish come from, the stripe may be edged with yellow or orange-red. Males are more colourful, females rounder.123
Personality what they are like
Peaceful and a little timid. It is happiest among other small, calm fish and in a group of its own kind.1
Daily activity how busy a day looks
A gentle fish that browses among plants and does not need large open swimming areas.2
Grooming and care the hands-on bits
Needs clean, soft water and stable conditions. Feed tiny foods often, including small live or frozen items for best colour.1
Home where they are happiest
A minimum footprint of about 45 x 30 cm (roughly 40 litres). Temperature 20-28 °C, pH 6.0-7.0, hardness 1-10 dGH. Dense fine-leaved plants recreate its marshy habitat.12
Food basics what goes in the bowl
A micropredator that probably grazes on zooplankton among plants. In the aquarium it eats freeze-dried Artemia and Daphnia, plus small live and frozen foods.12
Company who they like around
A schooling fish; keep a group of at least 8-10. Good companions are pygmy Corydoras, Otocinclus and shy anabantoids. Seriously Fish advises not mixing it with other Boraras species.1
The story where it all began
Maurice Kottelat described this fish in 1991 as Rasbora urophthalmoides, with its type locality in Pattani Province, Thailand. It was later transferred to the genus Boraras. It lives in marshes, swamps and ponds thick with aquatic plants.123
Fun facts for the dinner table
- 1
It is one of the smallest ray-finned fish species, with adults often only 12-16 mm long.3
- 2
Its common name comes from the long dark stripe and round tail spot that together resemble an exclamation mark.1
- 3
It has been found living in the moats around Angkor Wat in Cambodia.1
- 4
It spawns continuously in small batches and does not guard its eggs.1
Recognised by the official bits
- IUCN Red List
- Assessed as Near Threatened (February 2011)2
- FishBase
- Described by Kottelat in 19912
The care rhythm a typical week and year
A typical home-care rhythm for an Exclamation Point Rasbora. A starting point, not a vet's advice.
- FeedingSmall amounts once or twice a dayevery day
- Temperature checkevery day
- Water changeAbout 25% of the waterevery week
- Water testevery week
- Glass cleanevery week
- Filter rinseRinse in old tank water, never tap waterevery month
Owner questions the things everyone asks
How often should I feed my Exclamation Point Rasbora?
Feed your Exclamation Point Rasbora small amounts once or twice daily. Furry Diary's starting plan suggests feeding every day, offering only what they can eat in a couple of minutes. For exact amounts, check the food label and ask your vet.1 Pet Wiki plan
What does an Exclamation Point Rasbora eat, and what should it never eat?
These tiny fish are micropredators and enjoy freeze-dried Artemia and Daphnia, plus small live or frozen foods. Avoid large or hard foods that could harm them; for a safe diet, consult your vet or a good breeder.12
How much space does an Exclamation Point Rasbora need?
A minimum footprint of about 45 x 30 cm, which is roughly 40 litres, is recommended. Dense fine-leaved plants are ideal to recreate their marshy habitat.12
What temperature, light or water does an Exclamation Point Rasbora need?
Keep the water temperature between 20-28°C, pH 6.0-7.0, and hardness 1-10 dGH. Provide moderate lighting with plenty of plants; stable, clean water is essential for their health.12
How often should I clean an Exclamation Point Rasbora's home?
Furry Diary's plan suggests a weekly 25% water change, cleaning the glass, and testing the water each week. Rinse the filter monthly in old tank water, never tap water. Pet Wiki plan
Can an Exclamation Point Rasbora live with others?
Yes, they are peaceful schooling fish and should be kept in a group of at least 8-10. Good tankmates include pygmy Corydoras, Otocinclus, and shy anabantoids, but avoid mixing them with other Boraras species.1
How long does an Exclamation Point Rasbora live?
Lifespan varies depending on care and environment; ask your breeder or an exotic-pet vet for a more specific estimate based on your setup.
Can I handle an Exclamation Point Rasbora?
Handling is not recommended as these tiny fish are very delicate and easily stressed. If you need to move them, use a soft net and ask your vet for safe handling tips.
Written from the sources on this page, a few checked guides (VCA, ASPCA, RSPCA) and Pet Wiki's own starting care plan. A friendly guide, not a vet's advice.
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Every fact on this page has a numbered source. Spotted an error? [email protected].
- Seriously Fish - Boraras urophthalmoides seriouslyfish.comused for origin, size, water parameters, care, diet, behaviour, history
- FishBase - Boraras urophthalmoides fishbase.seused for author/year, IUCN status, size, habitat, feeding
- Wikipedia - Least rasbora en.wikipedia.orgused for names, size, history
Checked 2026-09-30. Text is written in our own words from these sources.