Red Knobby Starfish

Red Knobby Starfish (Protoreaster lincki) are large ornamental sea stars known for their bright red to orange coloration and distinctive raised black knobs that cover their body and arms. Native to sandy lagoons and shallow reef environments throughout the Indo-Pacific, these starfish slowly roam across the substrate and rockwork searching for food.

Their bold appearance makes them popular display animals in larger marine aquariums, though they require stable water conditions and a mature system to thrive long term.

Care Requirements

Care Level: Moderate to Difficult – Requires stable water quality and regular feeding
Minimum Tank Size: 75+ gallons
Aquarium Setup: Established aquarium with open sandbed areas, mature live rock, and stable salinity

Red Knobby Starfish do best in mature aquariums with plenty of space to move and forage. Stable parameters are extremely important, as sea stars are sensitive to rapid environmental changes.

Diet & Nutrition

Red Knobby Starfish are opportunistic scavengers that consume meaty foods, detritus, and naturally occurring organic material within the aquarium.

Diet: Omnivore/Scavenger – Feeds on meaty foods and organic matter

Recommended Foods:

• Mysis shrimp
• Chopped shrimp or clam
• Sinking carnivore pellets
• Small pieces of seafood
• Naturally occurring detritus and biofilm

Target feeding several times per week is often recommended, especially in cleaner aquariums with limited natural food availability.

Lifespan & Growth Rate

Lifespan: 3–5+ years
Growth Rate: Slow to Moderate

With stable water quality and consistent feeding, Red Knobby Starfish can maintain healthy tissue and coloration for many years.

Temperament & Compatibility

Temperament: Peaceful – Slow-moving scavenger
Reef Safe? Use Caution

Red Knobby Starfish are generally peaceful toward fish but may consume sessile invertebrates, soft corals, sponges, or other slow-moving organisms if underfed. They are often better suited for fish-only systems or carefully monitored reef aquariums.

Avoid housing them with triggers, puffers, large wrasses, harlequin shrimp, or other species known to prey on echinoderms.

Common Challenges & Considerations

Sensitivity to Salinity Changes

Red Knobby Starfish are highly sensitive to rapid changes in salinity and should always be acclimated slowly.

Starvation Risk

In aquariums without sufficient natural food sources or supplemental feeding, they may slowly decline over time.

Handling Sensitivity

Exposure to air and rough handling can damage delicate tissue and increase stress.

Limited Reef Compatibility

Some individuals may disturb or consume sessile invertebrates while scavenging throughout the aquarium.

Water Conditions

Temperature: 75–77°F
dKH (Alkalinity): 8–9
pH: 8.1–8.3
Specific Gravity: 1.024–1.026

Stable water chemistry, mature biological filtration, and regular feeding are important for maintaining healthy tissue and long-term success with Red Knobby Starfish.