Crystal tetra

Care at a glance

Overview

The crystal tetra is a tiny, almost transparent schooling fish that looks best in numbers, so keep a group of at least ten, and twenty in a planted tank makes a fine, drifting display. It swims in the middle of the water and is completely peaceful, suited only to small, gentle tankmates such as other nano tetras, pygmy corydoras, and small rasboras, since anything large will eat or outcompete it. Feed very small foods: fine flake, crushed micro pellets, microworm, cyclops, and baby brine shrimp. A group does well in around 40 liters or more, well planted and calm.

In the wild

Protocheirodon pi lives in quiet, clear to gently stained creeks of the upper Amazon in Peru and Brazil, drifting over sand in slow water. Keep it warm, from 23 to 28 degrees Celsius, at pH 5.5 to 7.2 with low to moderate hardness. Dense planting, driftwood, and a darker background give the group cover and make the transparent bodies easier to pick out, while calm water and dim light keep the fish out in the open.

Good to know

This transparent little characin, family Characidae, reaches only about 3.1 centimeters. Richard Vari first described it in 1978 as Leptagoniates pi, and in 2016 it was given its own genus, Protocheirodon, as an early offshoot of the Cheirodontinae. The species name pi refers to the Greek letter, from a small dark mark near the tail base. It is an egg scatterer, and aquarium breeding is not recorded.

Did you know

Richard Vari named it pi in 1978 after the Greek letter, for a small mark at the root of the tail; it is one of very few fish named for a mathematical symbol.

Tank mates

Crystal tetra is a peaceful, schooling species that keeps to the middle. These picks match on water type, temperature, pH, size and temperament.

• Fourspotted toothcarp

  Phallichthys quadripunctatus

  Freshwater

  1.4 in (3.5 cm)11 gal (40 L)68–86°F (20–30°C)
• Bumblebee otocinclus

  Rhinotocinclus isabelae

  Freshwater

  0.8 in (2 cm)11 gal (40 L)73–82°F (23–28°C)

• 

  Birdsong goby

  Stiphodon surrufus

  Freshwater

  1 in (2.5 cm)11 gal (40 L)73–81°F (23–27°C)

• 

  Borneo gold spot halfbeak

  Hemirhamphodon tengah

  Freshwater

  1.8 in (4.5 cm)11 gal (40 L)73–81°F (23–27°C)
• Dwarf thorny catfish

  Physopyxis lyra

  Freshwater

  1.4 in (3.5 cm)11 gal (40 L)73–82°F (23–28°C)

• 

  Espei rasbora

  Trigonostigma espei

  Freshwater

  1.5 in (3.8 cm)11 gal (40 L)73–82°F (23–28°C)

Check the full mix in the stocking calculator

Common questions

Related species

• 

  Micropterus tetra

  Hyphessobrycon micropterus

  Freshwater

  1.3 in (3.2 cm)12 gal (45 L)72–81°F (22–27°C)

• 

  Eilyos tetra

  Hyphessobrycon eilyos

  Freshwater

  1.2 in (3 cm)12 gal (45 L)72–81°F (22–27°C)

• 

  Weitzman's tetra

  Hyphessobrycon weitzmanorum

  Freshwater

  1.2 in (3 cm)12 gal (45 L)72–81°F (22–27°C)
• Scratched inpa tetra

  Inpaichthys parauapiranga

  Freshwater

  1.2 in (3 cm)14 gal (54 L)72–81°F (22–27°C)
• Axelrod's glass tetra

  Brittanichthys axelrodi

  Freshwater

  1.3 in (3.3 cm)14 gal (54 L)75–82°F (24–28°C)
• Redfin glass tetra

  Erythrocharax altipinnis

  Freshwater

  1.3 in (3.3 cm)14 gal (54 L)75–82°F (24–28°C)