Emperor tetra

Nematobrycon palmeri

FreshwaterFish

Care at a glance

Temperature: 73–81°F (23–27°C)
pH: 5.5–7.5
Adult size: 2 in (5 cm)
Minimum tank: 20 gal (75 L)
Temperament: Mostly peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Easy
Breeding: Medium
Rarity: Common
Origin: Colombia
Family: Characidae

Overview

Keep them in a group of six or more, ideally with a few females per male since males can squabble over territory. They are mostly peaceful and swim in the middle of the tank. A varied diet of quality flake, micro pellets, and frozen brine shrimp or daphnia keeps them in good shape. Aim for temperatures in the mid 20s C and a tank of around 75 liters or larger.

In the wild

Emperor tetras live in slow streams and rivers of the San Juan and Atrato basins in Colombia, usually under shade from overhanging plants. The water runs slightly acidic to neutral over sand or fine gravel. Give them a planted tank with subdued lighting and some open swimming room. They sit comfortably in soft to moderately hard water in the pH 5.5 to 7.5 range.

Good to know

A member of the family Characidae, this tetra reaches about 5 cm. It has an elongated body and a forked tail, with the middle rays of the caudal fin extended in males. It is an egg scatterer with no parental care, eggs hatching in roughly a day. The species is listed as Least Concern with stable wild populations.

Did you know

Adult emperor tetras have blue-green eyes that catch the light, which is unusual for a tetra. Watch a dominant male and you will also see him hold his fins flared and patrol a small patch of the tank, displaying to females and warning off rival males.