The Red Hook (Myloplus rubripinnis) is found throughout Northern South America in the Amazon, Rio Orinoco, and many of the other major river systems.  It has been collected in Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Suriname, and Venezuela from the densely vegetated slower moving rivers and streams in these regions.

In the aquarium trade, Red Hooks are often sold to tropical fish keeping enthusiasts as “Silver Dollars”  however, their red with black edged anal fin, noticeably smaller adipose fin, and larger adult size quickly distinguishes them from their Serrasalmidae cousins.

All Silver Dollar species are found in tropical climates and prefer weedy river tributaries, with dense overhanging vegetation that provides the low light conditions they prefer.

Like most Silver Dollars, the Red Hook is a peaceful, but skittish, schooling species.  They are herbivores that in their natural habitat voraciously feed on the leaves of submerged and marginal plants however, they are opportunistic feeders that also eat earthworms,  small crustaceans, grubs, insects, and smaller fish.

In an aquarium environment, Red Hooks needs a huge amount of vegetable matter in their diet to prevent them from decimating a well planted tank.

Red Hook (Myloplus rubripinnis)

The Red Hook (Myloplus rubripinnis) has a round, silvery, laterally compressed body with a long red pointed anal fin edged in black and a much smaller adipose fin.  They have small scales that give them a greenish blue sheen when viewed from different angles.

Although many tropical fish keeping enthusiasts say there is no way to differentiate between sexes, adult Myloplus rubripinnis can be sexed by the shape of their anal fin.  Females seem to have pinker bellies and an anal fin that points outward towards the tail, and then down to a point.    The anal fin in male Myloplus rubripinnis is usually somewhat longer and points almost straight down vertically, into the classic “J” shape.

Red Hooks do best in a densely planted, dimly lit aquarium of at least 75 gallon capacity, with a dark  sand or fine gravel substrate, some pieces of driftwood, a few well placed rocks for them to hide among,  and some floating plants to help diffuse any overhead lighting and reduce skittishness.    Hardy plants like Java Fern, Hornwort, etc. is recommended to minimize grazing.   They require good water quality and regular water changes.  A canister filter would be a good choice for this species to provide the water flow and quality necessary for their well being.

Because they are a schooling species, Myloplus rubripinnis do best when kept together with at least 5 or 6 other individuals in a single species biotope setup.   They are quite peaceful, and many tropical fish keeping enthusiasts successfully house Red Hooks with other larger peaceful fish in a community tank environment however, at least 3 or 4 should be kept together with plenty of hiding places to keep them from becoming too skittish, or reclusive.

As of December 5, 2017  Red Hooks (Myloplus rubripinnis) have been successfully bred in an aquarium environment by at least one individual named Anthony in Dayton, Ohio.  He was kind enough to let us know that he raised approximately 50 fry to adulthood in a 150 gallon tank.

All Silver Dollars require vegetable matter in their diet and the Red Hook is no exception.   They should be fed commercial algae wafers, Spirulina flakes, cucumbers, lettuce, peas, zuchinni, spinach, and other fresh greens.   They will also eagerly accept regular offerings of fresh, frozen, or freeze dried bloodworms, tubifex, earthworms, ghost shrimp, and brine shrimp.

Myloplus rubripinnis are usually readily available in tropical fish keeping shops and online at reasonable prices.   They are usually sold as juveniles when they are 1 1/2″ – 3″ or larger in size.

Red Hook (Myloplus rubripinnis)

Minimum Tank Size: 75 gallons
Care Level: Moderate
Temperament: Peaceful
Aquarium Hardiness: Moderately Hardy
Water Conditions: 73-81 °F°, <10dgH, pH 6.0-7.0
Max. Size: 10″ or more
Color Form: Silver, Red
Diet: Omnivorous (primarily Herbivorous)
Compatibility: Aggressive to small fish
Origin: Northern South America
Family: Characidae (Serrasalmidae)
Life Span: 5-10 years or more
Aquarist Experience Level: Intermediate