TankBud

Sailfin tetra

Crenuchus spilurus

Also known as Sailfin characin

FreshwaterFish

Sailfin tetra (Crenuchus spilurus)
The Wet Spot Tropical Fish · Used with permission

Care at a glance

Temperature
73–82°F
23–28°C
pH
5.0–6.5
Adult size
2.4 in
6 cm
Minimum tank
20 gal
75 L
Temperament
Mostly peaceful
Social behavior
Social
Swim level
Middle
Difficulty
Medium
Breeding
Medium
Rarity
Common
Family
Crenuchidae
Origin
Northern South America: Amazon and Orinoco basins plus coastal rivers of the Guianas (Guyana, Suriname, French Guiana)

Overview

Keep a small group of about six with more females than males, or just a pair, in a tank of 75 liters or up. They live in loose groups rather than tight schools, and males set up small territories, so an excess of females cuts down on sparring. They are mostly peaceful but timid, and they hover in open water among roots and leaf litter in the middle of the column. The water should run warm, 23 to 28 C, soft, and acidic at a pH of 5 to 6.5. This is a micropredator, so feed small live or frozen foods like baby brine, daphnia, moina, and grindal or microworms, since it often refuses dry food. Keep them with calm tankmates of similar size, and skip nano fish, fry, and dwarf shrimp, which they will eat. They are sensitive to organic waste, so run a well established tank with good water quality.

In the wild

Sailfin tetras come from soft, acidic blackwater in northern South America, across the Amazon and Orinoco basins and the coastal rivers of the Guianas. These are dim, slow stretches stained brown with tannins from leaf litter and fallen wood. To match that, give them a mature, dimly lit tank of 75 liters or more with sand, plenty of driftwood, and a layer of dried leaves on the bottom. Keep the water warm at 23 to 28 C, soft, and acidic at a pH of 5 to 6.5.

Good to know

Despite the name, this is not a true tetra. It sits in the family Crenuchidae, the South American darters, and tops out around 6 cm, with some northern fish reaching about 7 cm. It is a cave and substrate spawner with parental care: the male guards the eggs, which hatch in roughly 36 to 48 hours, and the fry are free swimming after another four to six days.

Did you know

Males earn the common name with a tall, flowing dorsal fin they flare during displays. When two males face off over a patch of territory, they spread those sails at each other and lock jaws in a short shoving match instead of doing real damage. Females stay plainer, with shorter fins.

Weekly picks

Tank mates

Sailfin tetra is a mostly peaceful, social species that keeps to the middle. These picks share a community profile with it, are safe together in both directions, and overlap on water type, temperature and pH.

Check the full mix in the stocking calculator

Common questions

What size tank does a Sailfin tetra need?

A Sailfin tetra needs at least 20 gal (75 L). It spends most of its time in the middle.

What temperature and pH does a Sailfin tetra need?

A Sailfin tetra is comfortable at 73–82°F (23–28°C) with a pH of 5.0–6.5.

How big does a Sailfin tetra get?

An adult Sailfin tetra reaches about 2.4 in (6 cm).

Related species