Darter characin

Apareiodon affinis

FreshwaterFish

Care at a glance

Temperature: 64–77°F (18–25°C)
pH: 6.0–7.5
Adult size: 7.1 in (18 cm)
Minimum tank: 53 gal (200 L)
Temperament: Mostly peaceful
Social behavior: Shoaling
Swim level: Bottom
Difficulty: Medium
Breeding: No record
Rarity: Rare
Origin: Paraná and La Plata basins, South America
Family: Parodontidae

Overview

The darter characin is a subtropical, bottom-hugging fish that lives in shoals, so keep a group of five or more to keep them calm and bring out natural behavior. It props itself on the substrate with its pectoral fins and darts from stone to stone, grazing the algae film, and it appreciates cooler water than most community tetras will accept. It is generally peaceful but active and can be pushy at feeding time, so give it a roomy tank of around 200 liters with a strong current and open, stony ground. It grazes aufwuchs and biofilm but also takes prepared foods, so offer algae wafers, vegetable flake, and small frozen items. Keep tankmates similar in size and happy in cooler water.

In the wild

This fish comes from the Parana and La Plata river systems of southern South America, flowing subtropical water that cools noticeably in winter. It lives over stone and gravel in well-oxygenated current, scraping algae and small creatures from hard surfaces. Match that with cooler water from about 18 to 25 C and a slightly acidic to neutral pH between roughly 6.0 and 7.5, kept clean and moving. A river-style tank with smooth rocks, gravel, and brisk flow suits it, and it does not want to be kept constantly warm, which shortens its life.

Good to know

Apareiodon affinis belongs to the Parodontidae, a small family of South American scrape-toothed characins built for life on the bottom of flowing rivers. It reaches up to about 18 centimeters and uses a downturned, chisel-like mouth to rasp algae from rock. It has no aquarium breeding record and arrives as wild-caught stock. The genus is a longstanding subject of genetics research because of the unusual chromosome systems found in the family.

Did you know

Some populations of this plain grey fish carry an unusual multiple sex chromosome system in which the females, not the males, hold the odd chromosomes, making it a favorite subject for scientists who study how sex chromosomes evolve.

Tank mates

Darter characin is a mostly peaceful, shoaling species that keeps to the bottom. These picks match on water type, temperature, pH, size and temperament.