Glass bloodfin tetra

Prionobrama filigera

FreshwaterFish

Care at a glance

Temperature: 73–81°F (23–27°C)
pH: 6.0–7.5
Adult size: 2.4 in (6 cm)
Minimum tank: 20 gal (75 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Middle
Difficulty: Easy
Breeding: Hard
Rarity: Common
Origin: South America
Family: Characidae

Overview

Keep them in a school of six or more in a tank of about 75 liters. They are peaceful, active fish that hold to the middle and upper water and suit a calm community. Aim for water in the mid 20s C and soft to neutral pH. In the wild they eat small insects, crustaceans, and zooplankton, so in a tank feed flake, micro-pellets, and the odd frozen daphnia or mosquito larvae. They mix fine with other small, gentle species.

In the wild

The glass bloodfin tetra lives in clear to lightly tannin-stained rivers of central South America, including the Paraguay, Parana, and Guapore basins. These are slow to moderate waters with plenty of plants and a fine sand or mud bottom. Recreate that with a planted tank, gentle flow, and soft to neutral water with pH from 6 to 7.5. Some open mid-water space is good, since these are busy swimmers.

Good to know

Prionobrama filigera is a characin in the family Characidae, reaching about 6 cm. Its body is largely transparent, so you can see internal structure through it, and the red tail fin gives it the bloodfin name. It is an egg scatterer with no parental care, and breeding it in a tank is difficult. The species is listed as Least Concern with stable wild populations.

Did you know

The see-through body is not just for looks. Transparency is a real defense in open water, since there is little for a predator's eye to lock onto, and it works best when many fish move together and break up any clear outline. It is part of why these tetras school so tightly when something startles them.