Red Knob Sea Star Care Guide
Protoreaster lincki is a western Indian Ocean sea star with bright red tubercles on a grey, grid-patterned body. Like the chocolate chip star, it is not reef safe.
Compiled by Aquairi from published sources · Published · Updated
Overview
Protoreaster lincki, the red knob sea star, is a five-armed asteroid of the family Oreasteridae from the western Indian Ocean. It is recognised by numerous bright red tubercles that rise from the arms, connected by red stripes over a grey body so that the surface resembles a grid of interconnecting wires. Its skeleton is built of many calcareous ossicles and spicules within layers of connective tissue. Although popular in the aquarium trade, its appetite for other invertebrates makes it a demanding tank inhabitant.
Taxonomy
- Class: Asteroidea
- Order: Valvatida
- Family: Oreasteridae
- Genus: Protoreaster
- Scientific name: Protoreaster lincki
- Authority note: WoRMS lists Protoreaster lincki (Blainville, 1830)
Habitat
The species inhabits the western Indian Ocean, mostly along the African coast and Madagascar, ranging north to India and Sri Lanka, with a small population reported at Coral Bay in Western Australia. It prefers sandy or muddy seabeds and occurs from shallow tidal pools down to about 100 m, and it remains active during both day and night.
Tank requirements
- Minimum tank volume: 300 L
- Temperature: 24–26 °C (75–79 °F)
- pH: 8.1–8.4
- Carbonate hardness (dKH): 8–11
- Specific gravity: 1.024–1.026
- Adult diameter: up to about 30 cm
- Lifespan: roughly 5–17 years
A large, established system with a deep sand bed and stable parameters suits this animal, and it should be acclimated slowly to avoid stress from rapid changes.
Diet
Protoreaster lincki is carnivorous and will eat soft corals, sponges, tube worms, clams and even other starfish. In captivity it must be target-fed meaty foods such as pieces of shrimp, clam or squid, since it cannot reliably sustain itself by grazing alone in a confined system.
Compatibility
This sea star is not reef safe; its broad invertebrate diet means it should be housed in fish-only-with-live-rock systems with peaceful, non-predatory fish. Keep it away from soft corals, clams and harlequin shrimp, which prey on sea stars.
Conservation status
The species has declined in places due to heavy collection for the curio trade, contributing to local rarefaction of populations.
Protoreaster lincki Breeding Guide: Red Knob Sea Star
Overview
Protoreaster lincki, the red knob or African sea star, is a large Oreasteridae sea star from East Africa and the Indian Ocean. It has a cream to grey body with prominent red conical projections. Like its congener Protoreaster nodosus, it is a predatory, non-reef-safe star best suited to fish-only systems.
Reproductive Mode
Protoreaster lincki is a gonochoric broadcast spawner, in line with the class Asteroidea. Species-specific spawning observations are limited, so reproduction is described using the general starfish pattern shared by the family.
Sexual Reproduction
During free spawning, eggs and sperm are released into the water and the embryos and larvae live as plankton. Larvae develop through bilaterally symmetrical bipinnaria and brachiolaria stages, then settle on the seabed and metamorphose into small pentaradial juveniles.
Common Challenges
The planktonic larval phase needs open-water dispersal and microfood that home systems cannot supply, so the cycle is not completed in captivity. No asexual reproduction is documented for this species. Because it preys on soft corals and clams, it is unsuitable for reef tanks.