Red Hook Silver Dollar (3.5”)

Scientific Name: Myloplus rubripinnis

The Red Hook Silver Dollar is a striking South American characin, admired for its disc-shaped silver body and vivid red markings on the anal fin and lower tail, resembling a "red hook." It is a peaceful but large shoaling species that requires proper space and care.

Maximum Size and Lifespan

• Size: Up to 9–10 inches (23–25 cm) in captivity, occasionally larger in the wild.

• Lifespan: Typically 10–12 years with good care.

Recommended Aquarium Size, Water Changes, and Care

• Tank Size: Minimum 75-125 gallons (475 liters) for a small group, as they are active shoalers. Larger is better for adult groups/community setups

• Water Changes: 25–40% weekly to maintain water quality.

• Water Parameters:

  • Temperature: 74–82°F (23–28°C)

  • pH: 5.5–7.5
    

• Care Level: Moderate. Needs open swimming space, strong filtration, and a group of 5+ to feel secure and display natural behavior.

Tankmates

• Compatible: Other large, peaceful South American species such as Severums, Geophagus, Oscars, Uarus, large tetras, Plecos, and peaceful catfish.

• Avoid: Very small fish (may be eaten), overly aggressive cichlids, or fin-nippers.

Diet

• Omnivorous with herbivorous preference.

• Main diet should include:

  • Fresh vegetables (spinach, peas, lettuce, zucchini)

  • Algae wafers

  • Quality pellets formulated for large omnivores/herbivores

  • Occasional protein (shrimp, bloodworms, insects) but not too heavy, as they need more plant matter.

Breeding

• Rare in captivity.

• In nature, breeding occurs during the rainy season.

• They scatter adhesive eggs among submerged vegetation.

• In aquariums, successful breeding is difficult due to their size, need for shoals, and space requirements.

Overview

The Red Hook Silver Dollar (Myloplus rubripinnis) is a large, striking, and peaceful characin that thrives in groups. Its disc-shaped silver body and vivid red anal fin give it a distinctive look among silver dollars. Best suited for large aquariums with open swimming areas and some cover, this species is hardy but requires careful attention to water quality and diet. They are excellent community fish with other robust, peaceful species, provided enough space is given.

Natural Environment

• Native Range: Widely distributed across the Amazon Basin and other South American river systems.

• Habitat: Slow-moving rivers, flooded forests, and backwaters with abundant submerged plants, roots, and driftwood.

• Role in the Wild: Primarily herbivorous, helping control aquatic vegetation, while also feeding on fallen fruits and detritus.