Fowler's hemiodus

Bivibranchia fowleri

Also known as Sand-sifting hemiodus, Eartheater hemiodus

FreshwaterFish

Care at a glance

Temperature: 75–84°F (24–29°C)
pH: 5.5–7.0
Adult size: 7.5 in (19 cm)
Minimum tank: 106 gal (400 L)
Temperament: Peaceful
Social behavior: Schooling
Swim level: Bottom
Difficulty: Difficult
Breeding: No record
Rarity: Rare
Origin: Guiana Shield rivers and lower Amazon
Family: Hemiodontidae

Overview

Fowler's hemiodus is a peaceful, sand-sifting characin that feeds by taking in mouthfuls of fine substrate and sorting the edible parts from the grains. Keep it in a shoal of six or more, since it is a social open-water fish that frets on its own. It works the bottom and lower water, so it needs a deep bed of soft sand it can actually process, never bare glass or coarse gravel. House it with calm, similarly sized companions and keep the water clean and well oxygenated, as this is a demanding fish. Feed sinking foods and small frozen items fine enough to pass its sorting, and give a group a long tank of about 400 liters or more.

In the wild

This fish lives over sand flats in the clear and blackwater rivers of the Guiana Shield and the lower Amazon, sifting the bottom for small invertebrates. A long tank with a real sand floor, gentle current, and high oxygen suits it best. The water should be soft and warm, about 24 to 29 C, at a pH of 5.5 to 7.0. Roots and scattered leaf litter help, but the open sand bed is the point.

Good to know

Bivibranchia fowleri is a member of Hemiodontidae and reaches about 19 centimeters. Its standout feature is a highly protrusible, tube-like mouth that extends to vacuum sand, letting a characin feed much as a South American eartheater cichlid does. Specialized gill structures help it separate food from grit. There are no records of it breeding in aquaria.

Did you know

It is a characin that behaves like an eartheater: the mouth shoots out into a soft tube, draws in a load of sand, and spills clean grit back out while keeping the food. Two very different fish families arrived at the same trick.