Fish, Tanks and Ponds

Fish, Tanks and Ponds
A comprehensive guide to fish

Hemiodus argenteus

Silver Hemiodus

Hemiodus argenteusHemiodus argenteus
Photos by Andy Rapson


Hemiodus: Greek, hemi = half + Greek, odous = teeth

General Notes:

All Hemiodus are very active and fast swimmers and initially very nervous although they will settle to a point they will never be fully confident and sudden movement by their tank or sudden loud noises could cause them to panic and injure themselves or even jump out of the water. Hemiodus are shoaling fish and appear more confident when kept in a group of at least six individuals. Hemiodus need very good water quality and a high oxygen content or they will be among the first fish to suffer.


Aquatic inverts make up a large of their diet and possibly smaller fish. In captivity Hemiodus are quite unfussy feeders and will readily take flake food, suitably sized pelleted food along live or frozen blood worms, glass worms, brine shrimps, daphnia and tubifex worms.


Generally peaceful but their hyper activity may intimidate more timid species. Hemiodus are also quite large when adult and they may regard smaller fish as food.


Not known, adult females may more rounded.


Hemiodus argenteus has never been bred in captivity. No details are available.

Wild status

Wild populations of Hemiodus argenteus have not been evaluated but the species is not thought to be facing any immediate threats.

Additional information

Hemiodus do best when kept in a large aquarium with large open spaces and a few planted areas to hide in. Ironically having somewhere to hide increases the fish's confidence and makes them less likely to do so.

Information at a glance

pH: 6 - 7.5
dGH: 4 - 12
Temperature: 22 - 28°C (72 - 82°F)
Diet: Omnivore
Size: 24cm (9.5in)
Min tank size: 250 litres.
Difficulty level: Moderate
Aquarium type: Community
Swimming level: Middle & lower

Distribution and habitat

distribution map for Helostoma temminckii

Origin: South America: Orinoco River basin; Japurá, Jutai, Negro, Tapajós, and Uatumã River basins; Rupununi, Corantijn, Itapecuru, and Mearim River basins.

Habitat: Rivers


Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Characiformes
Family: Hemiodontidae
Genus: Hemiodus
Species: H. argenteus. Pellegrin, 1909

Other common names:
Silver Hemiodus.

Hemiodopsis ocellatus,
Hemiodus ocellatus,
Hemiodopsis ocellata,
Hemiodopsis argenteus.