• Scientific name: Myloplus rubripinnis
• Synonyms: Aphyocharax rubripinnis, Myletes luna, Myletes rubripinnis, Myleus rubripinnis
• Common name: Red Hook Myleus, Red Hook Silver Dollar, Red Hook Pacu, Redhook Myleus
• Group: Characins
• Habitat: South America; Ecuador, Venezuela, Colombia, Guyana, Suriname, French Guiana, Peru and Brazil
• Size: 25 cm, in nature it can reach 39 cm in length.
• Biotope: Prefers calm zones of main rivers where the vegetation hangs over the river banks.
• Social behavior: A generally peaceful and active shoaling fish and can be kept with other larger peaceful species. They swim in the middle and top areas of the aquarium, so bottom-dweller tankmates would be a good choice. They might eat smaller fish.
• Diet: Herbivorous; They mainly eat the leaves of submerged or marginal vegetation in nature. In aquarium they accept almost any vegetable matter, such as courgette, cucumber, peas and spirulina algae, but they also eat flake foods and live foods such as bloodworm and brineshrimp.
• Breeding: Not successful in aquarium
• Tank: Minimum 300 litres
• Population: 5-6 fish for 550 litres
• Decoration: They require a heavily planted tank, with dim lighting. It could be tricky since these fish eat plants, driftwood and rock are suitable for their aquarium, although tougher bitter-tasting plants such as Java fern and Anubias species should survive, but will still need to be replaced regularly.
• Temperature: 23-27 °C
• pH: 6-7
• Hardness: 1-10 NK°
• Lifespan: 5-10 years

Description: Red Hook Myleus is a high sided fish which is laterally compressed. Myloplus rubripinnis has two color variants, the first has iridescent silver body, while the other has silver body with some orange spotting (Myloplus rubripinnis luna). Both have translucent fins, except the anal fin, which is curved and red with black edging, giving this fish its common name. Belonging to the subfamily Serrasalminae, which contains pirahna, pacus and silver dollars, the redhook silver dollar has strong jaws and a good set of teeth. These are usually used to eat plants rather than fish, although smaller fish will be taken. 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 shouldn’t be a problem. These peaceful fish need to be maintained in schools (at least 5 fish) to get the most out of them, as they are a social species that will shy away if kept singly or in pairs.

Mature males are smaller than females and have a little longer anal fin. There are no detailed reports of the breeding habits of Myloplus rubripinnis in the aquarium. In nature usually two males will get on both sides of the females and drive her to the bottom where they use the females hooked anal fin to guide the eggs into the substrate.