Not furry, but we like them anyway.
Rainbow Shark
Epalzeorhynchos frenatum
Also called Ruby shark, Red-fin shark, Rainbow sharkminnow, Green fringelip labeo, Whitefin shark
From Southeast Asia: the Mekong, Chao Phraya, Mae Klong and Xe Bangfai basins of Thailand, Laos and Cambodia.12
At a glance the quick version
Looks how to spot one
Slender bottom-dwelling minnow
A long, slim fish with a slightly downturned mouth. The wild form has a dark greenish-grey body set off by bright red fins. Males tend to be slimmer and more vivid, with dark lines edging the anal fin.123
Personality what they are like
Confident and strongly territorial, especially towards fish that look or behave like it. Usually best as the only one of its kind in the tank, with active mid- and upper-water tankmates chosen with care.23
Daily activity how busy a day looks
Active and always patrolling its patch of the tank bottom, so it needs floor space and lots of hiding spots.2
Grooming and care the hands-on bits
Keep a well-filtered tank with regular water changes. Water: about 20-27 C, pH 6.0-8.0, hardness about 2-15 dGH.21
Home where they are happiest
A tank of at least about 120 x 45 cm base (around 240 litres) for one fish, with rocks, wood and plants to break lines of sight. A lid helps as it can jump.21
Food basics what goes in the bowl
Mainly grazes on algae and the film on surfaces in the wild. In the aquarium give quality dried foods, vegetables and small live or frozen foods like bloodworm and brine shrimp.12
Company who they like around
A solitary fish; normally kept singly. If more than one is kept, each needs a large territory.2
The story where it all began
Henry Weed Fowler described the species in 1934, and it was later moved into the genus Epalzeorhynchos. It has been a long-standing favourite in home aquariums, where all stock is produced on farms.32
Fun facts for the dinner table
- 1
In the wet season it moves into flooded land, then returns to the river as the water drops.1
- 2
It is one of the species offered as genetically modified fluorescent GloFish.3
- 3
Although called a shark, it is a cyprinid, a relative of carp and minnows.3
- 4
With good care it may live for more than 15 years.2
Recognised by the official bits
- IUCN Red List
- Least Concern (assessed 2011).1
- Aquarium trade
- Aquarium fish are farm-bred; a genetically modified fluorescent version is sold under the GloFish brand.2
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Rainbow Shark. It is our own starting plan, not a vet's advice, and you can change every line in the app.
- 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
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The breed atlas is free for everyone, with a source on every fact, and it will never show ads. If it helped you, a small tip keeps the research going. Any amount is lovely, and no is a perfectly fine answer too.
Where this comes from
Every breed page shows where each fact comes from. If we got something wrong, sorry, we are pet people, not a science magazine. Tell us at [email protected] and we will fix it.
- FishBase: Epalzeorhynchos frenatum fishbase.seused for distribution, length, water, IUCN, diet, seasonal migration
- Seriously Fish: Epalzeorhynchos frenatum seriouslyfish.comused for care, tank, water, diet, behaviour, colour forms, lifespan
- Wikipedia: Rainbow shark en.wikipedia.orgused for other names, history, GloFish, colour forms
Checked 2026-09-30. Text is written in our own words from these sources.