The Silver Tetra, Ctenobrycon spilurus, is one of the larger South American Tetras. It comes from French Guiana, Guyana, Suriname and Venezuela, from the Orinoco River basin as well as coastal river basins of Suriname, Guyana, and French Guiana.
Silver Tetras grow up to 10 cm (4 inches) long. They are a deep bodied fish (flattened sideways) so they are quite big fish for their length. This makes it among the biggest of the fish normally referred to as tetras. Their live span is up to at least 5 years.
The Silver Tetra is almost disc shaped and this, as well as its mainly silver colour is responsible for a Russian name that means “coin”. The colour is basically silver, but there is a slight olive-green cast to some of these fish.
The eyes are large. There is some black at the base of their tail fin. Some have a small dark spot near their gill covers. The dorsal fin is fairly short. There is a variable amount of red in the fins under the fish.
The Silver Tetra is an omnivore in the wild, eating more plants than many of its relatives although it will certainly consume animal food like insect larvae, crustaceans and worms voraciously. It adapts well to normal aquarium foods. Some extra plant material will benefit this fish. The plant may be things like lettuce, Brussels sprouts, cabbage etc or aquatic plants. Duckweed is especially nutritious and I use quite a lot for my plant eating fish.
As well as plants, this fish, like most animals, benefit from a variety of food. If possible include some live food like mosquito larvae, daphnia, worms, etc as well as frozen food like bloodworms or brine shrimp.
This is a large fish and needs plenty of space. I suggest at least 150 litres (40 US gallons) as the minimum capacity. There should be plenty of space for swimming as well as plants but remember that this is a plant eating fish. If you have vigorously growing plants and give vegetable food like Duckweed to your fish regularly you should still be able to grow plants with Silver Tetras.
The Silver Tetra is all right up to about 20 degrees of general hardness. The pH can be between 6.5 and 7.5, and the temperature between 20 and 26 degrees C (between 68 and 79 degrees F).
This is a hardy and moderately adaptable fish. Some care is needed to keep the water quality high. This will normally include a good filter and frequent partial water changes.
The Silver Tetra is a fast-swimming midwater fish that is quite capable of jumping out of the water, so a good aquarium cover is necessary.
The Silver Tetra is a schooling fish and a minimum of 5 is suggested. This is another reason why you need a large aquarium to keep it in. It is not a particularly predatory fish, but because of its large size is unsuitable as a companion for small fish like Neon Tetras. I would also avoid putting it with slow moving fish with long fins.
The Silver Tetra is vigorous swimmer and would disturb some fish. Apart from this its lower temperature requirement makes it a poor companion for Discus.
Some suitable companions are the corydoras catfish like the Bronze and Peppered catfish as well as the larger species of tetras and other characins, barbs, some of the Cichlids, larger gouramis and similar sized fish.
The males tend to be thinner and more brightly coloured. The male’s anal fin is more rounded than the females.
The Silver Tetra is an easily bred fish. A mature female can produce 2000 eggs. They reach sexual maturity at 8-12 months old.
For breeding, I suggest a pH of 7, a hardness of 8-10 and a temperature of 24 degrees C. (75 degrees F). a water depth of 30 cm (1 foot is suitable. The fish will scatter their eggs over fine leaved plants or a similar medium.
The aquarium will need to be much bigger than most breeding tanks. Normally people breed this fish in pairs. Occasionally people have trouble in the selection of pairs.
Raising the Fry
After spawning, remove the parents. A partial water change at this stage is beneficial. The replacement water should be of the same temperature and chemical composition as the breeding tank water.
The eggs should hatch within one day and the babies should be free swimming after about 3 days. The ideal first food is paramecia and other infusoria. They will also eat commercial dried and liquid fry foods as swell as suspended boiled egg yolk.
The fry should soon be able to eat larger live foods like newly hatched brine shrimp, micro worms and finely screened daphnia.
The IUCN Red list has not evaluated this species. There is no special reason to consider it to be threatened.
Take proper precautions to prevent this fish from being introduced into waterways it is not native to.
The Silver Tetra is called the Silvertetra in Sweden, Sølvtetra in Denmark, Lanttitetra in Finland, Lambari in Brazil, Bobita in Venezuela, Серебристая тетра, Монетка (coin) or Рублик (Rouble) in Russia. In Mandarin Chinese it is called 栉啮鱼 or 櫛嚙魚 .
The accepted scientific name is Ctenobrycon spilurus (Valenciennes, 1850). Another name that has been used is Tetragonopterus spilurus Valenciennes, 1850
IUCN Red list: http://www.iucnredlist.org/apps/redlist/search