Red Knob Starfish

Red Knob Starfish requires a minimum of 75 gallons for healthy adults. The minimum is based on the species' adult size (12 inches), territorial range, and behavior pattern. Most Red Knob Starfish sold at small juvenile size will reach full adult size within 12-24 months and the system must be sized to the adult, not the juvenile.

The Red Knob Starfish needs a tank of at least 75 gallons, a temperature of 76-80°F (24-27°C) and pH 8.1-8.4. Adults reach about 12 inches and live 5-10 years. Best paired with peaceful tankmates of similar size and water-chemistry needs.

Red Knob Starfish requires standard reef parameters held tightly stable: Temperature: 76-80°F (24-27°C) Specific gravity: 1.025 (refractometer-measured) pH: 8.1-8.4 Alkalinity: 8-9 dKH Calcium: 420-450 ppm Magnesium: 1300-1400 ppm Ammonia + nitrite: Both 0 ppm Nitrate: Under 10 ppm Copper: 0 (lethal to invertebrates) Red Knob Starfish is sensitive to copper - never medicate the display tank with copper if Red Knob Starfish is present.

Red Knob Starfish is a omnivore. Eats a varied diet of pellets, frozen foods, and supplemental greens. Quality flake or pellet (Hikari, New Life Spectrum, Tetra) plus frozen mysis or bloodworms 2-3x weekly produces best color and behavior. Feed Red Knob Starfish appropriately for its size + activity level.

Red Knob Starfish is generally peaceful and compatible with most reef community species. Avoid keeping with predatory fish that view inverts as food: large wrasses (especially halichoeres + thalassoma), triggerfish, pufferfish, and certain large angelfish. Multiple Red Knob Starfish can share a tank but compete for food. Browse care guides for tankmate-compatibility tables for Red Knob Starfish and similar species.

Red Knob Starfish reaches 12 inches at adulthood with a captive lifespan of 5-10 years with proper care. Many marine inverts molt periodically; provide adequate calcium and a stable parameter regime to support healthy molts. The minimum is based on the species' adult size (12 inches), territorial range, and behavior pattern.

Red Knob Starfish is sensitive to copper, ammonia spikes, low oxygen, and rapid parameter swings. NEVER use copper medications in a tank with Red Knob Starfish. Symptoms of stress: reclusive behavior, color loss, refusal to feed, abnormal molting (incomplete or stuck molts). Most Red Knob Starfish deaths trace back to acclimation shock or parameter mismatch - drip-acclimate over 45-60 minutes when adding to a new tank.

Red Knob Starfish (Protoreaster lincki) is native to Indo-Pacific reef ecosystems, with wild populations distributed across coral reefs, sandy lagoons, and rocky tide pools. Captive specimens are typically wild-collected; some species are starting to be aquacultured but most Red Knob Starfish sold today still comes from wild reef collection. Sustainable sourcing matters - look for vendors who can verify their collection practices, and consider aquacultured alternatives when available.