At a glance the quick version
Looks how to spot one
Slim, laterally flattened characin (tetra) without an adipose fin
A slender, flat-sided tetra with a bold dark band running from eye to tail, edged with a shimmer of blue. The fins are washed with yellow and the tail ends in a three-pointed shape, with the middle rays extending into a short filament in males. Males are bigger, with longer fins and metallic blue eyes; females have green eyes. Under soft light and floating plants the body takes on purple tones.32
Personality what they are like
A calm, dignified tetra and a great choice for a general community tank. Males stake out favourite spots and display their fins to one another, which shows off their colours.21
Daily activity how busy a day looks
Moderately active; it cruises the middle of the tank and likes planted areas with some open water.2
Grooming and care the hands-on bits
Easy to keep in clean, stable water. Soft lighting and some floating plants help bring out its deepest colours.21
Home where they are happiest
Tank with a base of at least 90 x 30 cm (about 81 litres). Water 23-27 °C, pH 5.0-7.5 (FishBase gives up to 8.0), hardness 1-12 dGH. A well-planted tank with gentle flow suits it.21
Food basics what goes in the bowl
A micropredator that eats small insects, worms and zooplankton in the wild. In the aquarium it accepts dried foods; add regular small live or frozen foods such as Daphnia and brine shrimp for best colour.21
Company who they like around
Keep at least 6, ideally 10 or more. Good companions include livebearers, danios, rasboras, Corydoras, gouramis and dwarf cichlids.21
The story where it all began
Carl H. Eigenmann described the emperor tetra in 1911, naming it after Mervyn George Palmer, an English traveller who collected the first specimens in Colombia. It reached the aquarium hobby around 1960 and has been widely bred in captivity ever since.321
Fun facts for the dinner table
- 1
It is named after Mervyn George Palmer, an English collector who travelled in Central and South America.3
- 2
You can tell the sexes apart by eye colour: males have blue eyes and females have green eyes.2
- 3
Unlike most tetras it has no adipose fin, which helps tell it apart from the similar royal tetra.2
- 4
In a large planted tank a single pair will often spawn without any special help.3
Recognised by the official bits
- IUCN Red List
- Data Deficient (assessed 9 October 2014)1
- FishBase
- Used commercially in the aquarium trade1
The care rhythm Furry Diary remembers it for you
A typical home-care rhythm for a Emperor Tetra. 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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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 support@furrydiary.app and we will fix it.
- FishBase species summary: Nematobrycon palmeri fishbase.seused for describer, maximum length, distribution, water range, IUCN status
- Seriously Fish species profile: Nematobrycon palmeri seriouslyfish.comused for aquarium care, water parameters, behaviour, diet, sexing, habitat
- Wikipedia: Emperor tetra en.wikipedia.orgused for taxonomy history, etymology, appearance
Checked 2026-09-30. Text is written in our own words from these sources.