Emperor Tetra Origin and Appearance
The emperor tetra (Nematobrycon palmeri) comes from fast-flowing rivers in Colombia, and is one of the larger, deeper-bodied tetras we stock, reaching around 4-5cm, noticeably chunkier than a neon or cardinal tetra. Males develop a long, elegant lyre-shaped tail and a dark stripe running through the eye and along the body, with an overall purple or blue sheen depending on the lighting and the individual fish.
Purple Emperor Tetra vs Blue Emperor Tetra
You’ll sometimes see emperor tetras sold as “purple” or “blue” forms. These aren’t different species, but rather a natural variation in the intensity and tone of the fish’s iridescent colouring, which can also shift slightly depending on mood, lighting and water conditions. Both forms have identical care requirements, so the choice really comes down to which shade you prefer.
Emperor Tetra Tank Requirements
Emperor tetras do best in groups of six or more, though as a slightly less frantic shoaler than many smaller tetras, they’re often seen loosely grouped rather than in a tight ball. A tank of 60 litres upwards with plenty of planting and some open swimming space suits them well. Keep water at 23-27°C, slightly soft and acidic to neutral, with stable, mature filtration.
Feeding and Tank Mates
Emperor tetras take flake, micro pellets and small frozen foods such as daphnia and brine shrimp readily. Their slightly larger size means they can be kept alongside other peaceful community fish including Corydoras, gouramis and other larger tetra species without being outcompeted for food. Our guide to the best tetras for community tank setups suggests good companions. See our full range of tetra fish to plan a mixed shoal.
For more on tetras and other small shoaling fish, see our guide to choosing tetra tank mates.
Emperor Tetra FAQs
What’s the difference between a purple and blue emperor tetra?
They’re the same species with natural variation in colour intensity and tone rather than separate varieties, and both have identical care needs.
How big do emperor tetras get?
Around 4-5cm, making them noticeably larger and deeper-bodied than smaller tetra species like the neon or ember tetra.
How many emperor tetras should I keep together?
A group of six or more is recommended, though they shoal a little more loosely than smaller tetra species.