Drab Sole

Achirus achirus

FreshwaterBrackishFish

Care at a glance

Temperature: 77–86°F (25–30°C)
pH: 6.0–7.5
Adult size: 14.6 in (37 cm)
Minimum tank: 98 gal (370 L)
Temperament: Peaceful
Social behavior: Solitary
Swim level: Bottom
Difficulty: Medium
Breeding: No record
Rarity: Very rare
Origin: South America
Family: Achiridae

Overview

The drab sole is a peaceful, solitary bottom-dweller that spends the day buried in soft sand with only its eyes showing and comes out to feed after dark. It bothers nothing it cannot eat, but small fish and shrimp resting on the bottom may be taken at night, so choose tankmates that use the upper water and are not tiny. Give it a large area of fine, soft sand to bury into and gentle water flow. Feed sinking meaty foods such as bloodworms, tubifex, chopped prawn, and mussel, ideally in the evening. It grows large and needs floor space, so a broad tank of around 370 liters or more suits it. It stays healthiest with a little marine salt in the water.

In the wild

The drab sole ranges through the coastal rivers, estuaries, and lagoons of tropical South America and beyond, moving between fresh and brackish water along the lower reaches of rivers. It is often sold as a freshwater fish, and it can live in fresh water, but most keepers find it does best with a little salt added, at a low-end brackish strength. Give it warm water from 25 to 30 C, a pH between 6 and 7.5, and a deep, soft sand bed. Keep decor simple and open so it has room to glide and bury along the bottom.

Good to know

The drab sole belongs to the family Achiridae, the American soles, a group of flatfishes. Adults can reach around 37 cm, making it far larger than most soles sold for aquariums. Like other flatfishes it starts life symmetrical, then one eye migrates across the head as it settles onto its side, so the adult lies flat with both eyes on the upper surface. Its mottled brown coloring lets it disappear against the substrate. Aquarium breeding is not documented, and these fish are collected from the wild.

Did you know

Like all soles, the drab sole is not born flat. It hatches as an ordinary upright larva with an eye on each side, and as it grows one eye slowly travels over the top of the head to join the other. The adult then lives lying on its side, both eyes facing up, watching for food to pass overhead.