Threadfin acara

Acarichthys heckelii

FreshwaterFish

Care at a glance

Temperature: 75–86°F (24–30°C)
pH: 6.0–7.5
Adult size: 7.9 in (20 cm)
Minimum tank: 53 gal (200 L)
Temperament: Mostly peaceful
Social behavior: Social
Swim level: Middle
Difficulty: Difficult
Breeding: Hard
Rarity: Rare
Origin: Colombia, Peru, Brazil, Guyana
Family: Cichlidae

Overview

The threadfin acara is a medium-sized eartheater with long, trailing fins that is mostly peaceful outside of breeding and does well in a group with room to establish a loose hierarchy. It spends much of its time near the bottom, sifting sand for food, so a soft sandy floor is important to protect its mouth. It can become territorial and pushy when spawning, but it generally coexists with robust, similarly sized tankmates such as larger tetras, other calm cichlids and peaceful catfish. Provide open sand for foraging, plus driftwood, rocks and the odd cave. Feed sinking pellets along with frozen and live foods such as bloodworm and brine shrimp. A tank of at least 200 liters gives a group space to sift, swim and sort out territories.

In the wild

The threadfin acara ranges across the Amazon basin through Colombia, Peru, Brazil and Guyana, living over sand in slow rivers, lakes and flooded areas. The water is warm and ranges from soft and acidic to near neutral, so aim for a pH of 6.0 to 7.5 and a temperature of 24 to 30 C. The single most important feature is a deep bed of fine, soft sand, since this fish both sifts it for food and digs into it to breed. Add driftwood and some rockwork for structure, and leave open areas of sand where the fish can forage naturally.

Good to know

Acarichthys heckelii is a member of the cichlid family, Cichlidae, and grows to around 20 cm, with a long, trailing extension to the dorsal fin that gives the threadfin its name. It has an unusual way of breeding for a cichlid, digging a chamber in the sand reached by one or more long tunnels. The female excavates and defends the burrow and lays her eggs deep inside, while the male guards the entrances. This tunnel-nesting habit makes breeding in the aquarium difficult without a deep sand bed and the right conditions to trigger it.

Did you know

The threadfin acara breeds in the ground, digging a nesting chamber in the sand that is reached through one or more long tunnels. In this species it is the female that excavates the burrow and does much of the courting, the reverse of the usual cichlid arrangement.