Emperor Tetra

Nematobrycon palmeri

Emperor Tetra (Nematobrycon palmeri) is a peaceful freshwater fish that reaches about 4.2 cm (1.7 in) and swims in open water in a shoal. It wants 73–81°F (23–27°C) and pH 5–7.5, is kept in groups of 6 or more, and needs a tank of at least 81 L (21 gal).

At a glance

Type	Fish
Adult size	4.2 cm (1.7 in)
Minimum tank	81 L (21 gal)
Group size	6 or more
Temperature	73–81°F (23–27°C)
pH	5–7.5
Temperament	Peaceful
Lifespan	3–6 years
Eats shrimp	Shrimplets only

Before it goes in

Emperor Tetra needs at least 81 L (21 gal). The smallest size in this library that clears that is the 60H Tall.
Keep 6 or more. Below that it hides, colours down and is far more likely to be picked on.
Adult shrimp are safe; shrimplets will be eaten, so a shrimp colony will not grow in the same tank.
It is the wrong size to share a tank with Goldfish, Angelfish and Axolotl: it ends up as food.
It holds at 73–81°F (23–27°C). That shares a window with Betta and Cherry Shrimp, but not with Discus.
A group of 6 takes up roughly 36% of what a 60H Tall will comfortably hold, so plan the rest of the stock around it.

What tank size does it need?

At least 81 L (21 gal). The smallest size here that clears it is the 60H Tall.

How many should I keep?

6 or more. Fewer than that and it spends its time hiding instead of out in the open.

Will it eat shrimp?

Adults are safe, shrimplets are not. You can keep shrimp with it; you just will not get a growing colony.

What water does it want?

73–81°F (23–27°C), pH 5–7.5.

How long does it live?

3–6 years in a tank that suits it. That is how long you are signing up for.

Good tank mates

Tank mates from this library that share its temperature window, are peaceful and eat neither it nor its young: Cherry Shrimp, Bristlenose Pleco, Celestial Pearl Danio, Molly and Otocinclus.
Plants that hold up with it: Hygrophila corymbosa 'Siamensis', Water Sprite, Anubias nana 'Petite' and Cryptocoryne wendtii.

Often compared with

	Emperor Tetra	Glowlight Tetra	Lemon Tetra
Adult size	4.2 cm	4 cm	4 cm
Min tank	81 L	60 L	72 L
Group	6+	6+	8+
Temperature	73–81°F (23–27°C)	72–82°F (22–28°C)	68–82°F (20–28°C)
Eats shrimp	Shrimplets only	—	Shrimplets only

More livestock

Plan a tank with Emperor Tetra →

Sources (4) · checked Sep 2026