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Myloplus rubripinnis

Redhook

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Last revised 2026Edit this page

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Myloplus rubripinnis juvenile
Myloplus rubripinnis juvenileJJPhoto

Quick factsEdit

Max size
250mm SL10in SL
Aquarium size
180 × 38cm72 × 15in
Temp
23–27°C73–81°F
pH
6.0–7.0
Hardness
0–10dGH

Difficulty5 of 8 measures

Difficult

How the rating is worked out

Space
very large tank
Water
needs a steady pH
Temp
needs a steady temperature
Diet
unknown
Temperament
eats smaller fish
Social
needs to be in a group
Compatibility
unknown

Other demands

Each of these can raise the rating on its own, whatever the measures above say.

Hardiness
unknown
  • Needs a very large tank

The redhook, Myloplus rubripinnis, is a relative of the silver dollars from much of northern South America, including the Amazon and Orinoco. Commonly sold as a silver dollar, it can be told apart by its black-trimmed, red anal fin and grows much larger, to around 25 cm. Given a large enough aquarium, correct feeding and good water quality it should not pose many problems. It is still widely referred to as Myleus rubripinnis.

Distribution

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This species occurs over much of northern South America. It's been recorded from Ecuador, Venezuela, Colombia, Guyana, Suriname, French Guiana, Peru and Brazil. It occurs in a number of major river systems, including the Amazon and Rio Orinoco.

Usually found in slower-moving sections of rivers, especially where growth of marginal or overhanging vegetation is dense.

Aquarium size

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Standard length
250mm SL10in SL
Aquarium base
180 × 38cm72 × 15in
Volume
~260litres~69US gal

A group of adult fish will require a tank of at least 180 ∗ 38 ∗ 38 cm72 ∗ 15 ∗ 15 in - ~260 litres~69 US gal. Length and width are more important than height. Juvenile fish can be housed in smaller aquaria.

Maintenance

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Inhabits densely planted river tributaries in the wild. The difficulty in replicating this in captivity is that the species is an avid plant-eater! Hardy plants should be chose but will still need to be replaced regularly. Artificial plants could be used as an alternative as some of the fabric and silk-type plants that are now available make convincing fakes. Redhooks can be nervous fish, so dim lighting and areas of refuge will boost their confidence.

Water conditions

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Temperature
23–27°C73–81°F
pH
6.0–7.0
Hardness
0–10dGH

Temperature: 23 – 27 °C73 – 81 °F

pH: 6.0 - 7.0

Hardness: Up to 10°H

These recommendations come from this profile’s own figures. They contain affiliate links, so we may earn a commission.

A herbivorous species, in nature it feeds chiefly on the leaves of submerged or marginal vegetation, including terrestrial plants. Provide a large amount of vegetable matter in the diet, including; courgette, cucumber, peas, spring greens and other green vegetables. Commercial foods such as algae wafers, spirulina and vegetable flake are also recommended. Silver dollars will also accept the majority of aquarium foods and will relish such treats as bloodworm and brineshrimp.

Behaviour and compatibility

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Best kept in groups of at least five fish. Generally peaceful community fish and can be kept with other larger peaceful species. Much smaller fish may be eaten. Larger peaceful catfish such as plecos and doradids would be a good choice.

Sexual dimorphism

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Not known - male may have longer anal fin.

Reproduction

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Not achieved in the hobby.

Notes

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The Redhook is another species commonly sold as a Silver Dollar in the trade. It can be distinguished from those species as the black-trimmed, red anal fin is much more obvious than any of the metynnis species. The Redhook is also capable of growing much larger than its Silver Dollar relatives. This species was until recently referred to as Myleus rubripinnis and is still widel y referred to as such.

The Redhook is sometimes described as a difficult fish to care for but, given a large enough aquarium, correct feeding and good water quality, it should not pose many problems.

Distribution

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