Emperor tetra
Nematobrycon palmeri
easy careOverview
The emperor tetra (Nematobrycon palmeri) is one of the most elegant small tetras, with a bold black lateral stripe, a purple-blue sheen and, in males, a striking trident tail and blue eyes. Peaceful, hardy and long-lived, it brings understated class to a planted community. Males display constantly among themselves, adding movement and interest without real aggression.
Tank & water
A shoal is comfortable in 75 litres (20 gallons) or more with plenty of planting. Key requirements:
- Temperature: hold a steady 23–27 °C with a heater.
- Soft, acidic water: they show best colour at pH 5.0–7.5 and low to moderate hardness.
- Gentle filtration: an efficient filter with calm flow keeps water clean without stress.
- Planting and shade: dense plants, driftwood and subdued light bring out their purple tones and settle them.
Feeding
Emperor tetras are easy omnivores. Offer a quality flake or micro-pellet staple with regular frozen or live foods — daphnia, bloodworm, baby brine shrimp — to intensify colour and condition. Feed modest amounts once or twice a day. A varied diet keeps males in top display form.
Tankmates
They mix well with other peaceful community fish: cardinal tetras, rummynose tetras, harlequin rasboras, corydoras and dwarf cichlids like the bolivian ram. Avoid large or aggressive fish. Keep at least six so their social behaviour has an outlet — browse best fish for a planted tank for more ideas.
Common mistakes to avoid
- Keeping only one or two, which stresses them
- Bright, bare tanks that wash out their colour
- Hard, alkaline water at the extreme of their range
- Boisterous tankmates that outcompete them at feeding
Give emperors a soft-water, planted tank and a proper group, and their quiet elegance makes them a favourite that keepers return to again and again.
Emperor tetra — frequently asked questions
Are emperor tetras peaceful?
Yes, they are peaceful community fish, though dominant males display and spar with one another without causing harm. Keeping a group with a few females spreads out this behaviour and shows off their colours.
What water do emperor tetras need?
Soft, slightly acidic water suits them best, around pH 5.0–7.5. They are adaptable once acclimatised but colour up strongest in a well-planted, dimly lit tank with mature, stable water.
How do I tell male from female emperor tetras?
Males are larger and more colourful, with a longer trident-shaped tail extension and blue eyes; females are smaller, rounder and plainer with green eyes. A mixed group brings out the best displays.
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