Emperor Tetra (Nematobrycon palmeri)

Emperor Tetra (Nematobrycon palmeri)

Emperor Tetra (Nematobrycon palmeri)

The Emperor Tetra (Nematobrycon palmeri) is a peaceful fish that is native to the Atrato and San Juan river basins in western Colombia.

Most tropical fish keeping enthusiasts find the Emperor Tetra to be a perfect candidate for the community aquarium.

The Emperor Tetra has a long, slim flattened body with sickle shaped dorsal, pectoral, and anal fins. The fish has a silvery body with a black line placed within a purplish blue stripe that runs the entire length of its body. Its fins are translucent yellow.

Males can easily be distinguished from females by their eyes, fins, and black stripe. The males have metallic blue eyes while the female’s eyes are metallic green. The male has a pronounced three pronged tail, with the medial black stripe extending beyond the rest of the tail. In females, the black stripe only reaches the clear part of the tail. Males are usually larger than females and their anal fins are longer. The caudal fin the the male is also more pointed than in females.

Emperor tetras prefer soft water, a pH of 6.5, and a temperature range between 73° and 80° F.  They do not school like Neon and Cardinal tetras, but when in large groups when cool water temperatures are encountered, they will briefly come together in large shoals.  Emperor Tetras are one species that appears to be content when paired together.

In an aquarium, they can be housed with other peaceful soft water to brackish water fish.  They do better with subdued lighting and should have their tanks densely planted in river sand and aquascaped with plenty of rocks and driftwood for them to hide in. Floating water plants will help mimic their natural habitat, provide additional cover and bring out the purple hues of these beautiful fish.

Emperor Tetras will occasionally breed in an aquarium environment. They need a large well planted tank with slightly acidic water and preferably, no other fish. Usually no extra stimulation is needed and a majority of fry will survive in the tank if the parents are well fed, without the necessity of transferring the fry to a breeding tank.

In a densely planted established aquarium the fry will have algae, protozoa, etc. to eat and as they grow, you can provide them with daphnia and crushed dry flake food.

Emperor Tetras are omnivores and will eat brine shrimp, daphnia, freeze dried bloodworms, tubifex, micro pellets and high quality flake foods.

When available for purchase, these intriguing tetras are usually 3/4″ to 1-1/4″ in size.

Emperor Tetra (Nematobrycon palmeri)

Emperor Tetra (Nematobrycon palmeri)








Minimum Tank Size: 10 gallons
Care Level: Moderate
Temperament: Peaceful
Water Conditions: 72-77° F, KH 4-8, pH 6.0-8.0
Max. Size: 1½”
Color Form: Black, Purple, Silver
Diet: Omnivore
Compatibility: Excellent in peaceful community tanks
Origin: Colombia, South America
Family: Characidae
Lifespan: 6 years
Aquarist Experience Level: Experienced

2 Responses to “Emperor Tetra (Nematobrycon palmeri)”


  1. […] Rainbow Tetras (Nematobrycon lacortei) share many of the same traits as the Emperor Tetra (Nematobrycon palmeri), other characteristics readily distinguish the species from each […]

  2. […] acidic, tannin stained waters in forested areas of their range and are often confused with the Emperor Tetra (Nematobrycon palmeri).   They are easily distinguished by the fact that Inpaichtys kerri possess an adipose fin, which […]

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