At a glance the quick version
FishBase gives 12 cm standard length for males (10 cm females); Wikipedia and Seriously Fish give up to 15 cm.
Looks how to spot one
Scales, high-backed rainbowfish
A sizeable rainbowfish whose males develop a tall, arched back with age. Scales give a glittering salmon-red sheen in males, while females stay slimmer.32
Personality what they are like
Very peaceful but somewhat skittish, settling better in a larger group. Dominant males show the strongest colour.23
Daily activity how busy a day looks
Active swimmer that needs a long tank with open swimming space.21
Grooming and care the hands-on bits
Keep water hard and alkaline and offer a varied diet with some live food to keep colour strong. A cover helps with this active fish.2
Home where they are happiest
Minimum about 120 x 30 x 30 cm (around 108 litres); FishBase suggests at least 100 cm length. Temperature 22-25 C per Seriously Fish (FishBase lists 29-30 C), pH 7.0-8.2, hard water (about 10-20 dGH). Planted areas with open water.21
Food basics what goes in the bowl
Accepts dried, frozen and live foods; live foods help bring out the red colour.2
Company who they like around
Keep in a shoal of at least 6 to 8 (FishBase says 5 or more). Good tankmates include other rainbowfish, barbs, danios, characins and catfish.21
The story where it all began
Max Weber described the species in 1907 from Lake Sentani in northern New Guinea, the only place it lives in the wild. It breeds readily in captivity and has become a regular in the aquarium trade.31
Fun facts for the dinner table
- 1
Its only natural home is Lake Sentani, which it shares with another rainbowfish, Chilatherina sentaniensis.3
- 2
In slightly cooler water all males tend to turn red, while in warmer water mostly the dominant male shows full colour.2
- 3
Its scientific name is often spelled incisus, but incisa is correct because the genus Glossolepis is feminine.3
- 4
Eggs are scattered among plants and hatch in about a week.3
Recognised by the official bits
- IUCN Red List
- Endangered (assessed 5 December 2019)1
- Taxonomy
- Family Melanotaeniidae; described by Max Weber in 1907; correct spelling is incisa because the genus name is feminine3
The care rhythm a typical week and year
A typical home-care rhythm for a Red Rainbowfish. 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 Red Rainbowfish?
Furry Diary's starting plan is to feed small amounts once or twice a day. Your Red Rainbowfish accepts dried, frozen and live foods, and live foods help bring out its red colour. Always follow the food label and check with your vet for exact portions.2 Pet Wiki plan
What does a Red Rainbowfish eat, and what should it never eat?
Your Red Rainbowfish eats dried, frozen and live foods, with live foods especially good for colour. Never feed anything not listed; if unsure, ask your vet. A varied diet keeps it healthy.2
How much space does a Red Rainbowfish need?
Your Red Rainbowfish needs a long tank with open swimming space, minimum about 120 x 30 x 30 cm (around 108 litres). FishBase suggests at least 100 cm length. It's an active swimmer, so a longer tank is better.21
What temperature, light or water does a Red Rainbowfish need?
Keep water hard and alkaline: temperature 22-25°C (Seriously Fish) or 29-30°C (FishBase), pH 7.0-8.2, hardness 10-20 dGH. Provide planted areas with open water and a cover helps this active fish. Check temperature daily.21 Pet Wiki plan
How often should I clean a Red Rainbowfish's home?
Furry Diary's plan suggests a weekly water change of about 25%, weekly glass cleaning and water testing, and rinsing the filter monthly in old tank water (never tap water). Regular cleaning keeps the water quality good. Pet Wiki plan
Can a Red Rainbowfish live with others?
Yes, keep your Red Rainbowfish in a shoal of at least 6 to 8 (FishBase says 5 or more). Good tankmates include other rainbowfish, barbs, danios, characins and catfish. They are very peaceful but skittish, so a larger group helps them settle.21
How long does a Red Rainbowfish live?
Lifespan varies; no specific information is provided. Ask your vet or a good breeder for typical longevity in home aquariums.
Can I handle a Red Rainbowfish?
It's best not to handle your Red Rainbowfish; they are skittish and have delicate scales. Use a net only when necessary, and always with care.2
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.
Where this comes from
Every fact on this page has a numbered source. Spotted an error? [email protected].
- FishBase: Glossolepis incisa summary fishbase.seused for origin, size, water parameters, IUCN status, group size
- Seriously Fish: Glossolepis incisus seriouslyfish.comused for care, tank size, diet, behaviour, colour notes
- Wikipedia: Red rainbowfish en.wikipedia.orgused for other names, colours, history, naming
Checked 2026-09-30. Text is written in our own words from these sources.