Starfish belong to the phylum of echinoderms. The typical feature of the echinoderms is that they are radially symmetrical with five rays. In the case of the starfish, this is most visible with its 5 arms. There are about 1600 species that can be found in the oceans worldwide.
Starfish do not have eyes. However, there are several light-sensing cells at the tips of their arms to be able to perceive differences in brightness in their surroundings. Starfish also have chemoreceptors on their skin that allow them to detect nearby prey. They can also detect the gradient of the water’s salinity and move to the area where they prefer to live.

They move with feet on the underside of their arms that look like suction cups.
In the middle of the body, also on the underside, is the mouth opening. This makes it invisible to us divers. Depending on the genus, starfish feed on algae and mud on the one hand, others are scavengers and the predatory hunters among the starfish eat molluscs, snails and even crabs.
Reproduction takes place in different ways. There are separate-sex species, hermaphrodites, hermaphrodites and asexual reproduction. Fertilisation does not occur in direct contact, but takes place in the open water. As a free-swimming larva, it attaches itself to the bottom and then undergoes metamorphosis to become a juvenile starfish, as we see and know it with its 5 arms.

GHARDAQA STARFISH

Fromia ghardagana

Wine red colour with white spots. Is small, max. 8 cm and very rarely seen. This is because it is mainly nocturnal and hides in crevices during the day.
It is only found in the Red Sea and Mauritius.

PEARL STARFISH

Celerina cf. heffermanni

Its body is mostly red with many bright dots of different sizes spread over its arms like pearls. It lives on sand, in lagoons and protected reef slopes. This is also one of the smaller species and grows up to 10 cm in size.

SPINY STARFISH

Fromia nodosa

Its colour ranges from yellowish to orange to bright red. The thorn-like attachments on its arms are typical and give it its name. It lives on rubble, stones and living corals. Distribution In the Red Sea as far as the Maldives.
It can grow up to 15 cm.

WATSON STARFISH

Gomophia watsonie

The spines of are conical and have bright, mostly blue tips.
It looks very similar to the spiny starfish. The colour varies from pink to brown. It lives mainly in the Indo-Pacific from Palau to New Caledonia. Rarer in the Red Sea.

BUMPY STARFISH

Echinaster callosus

Typical for this starfish are the bumps, which are spread all over the body. Colour from orange to red. It prefers shady places on reef tops and outer reef slopes during the day. This nocturnal animal lives in the Red Sea to Polynesia and can grow up to 25 cm.

COMB STARFISH

Astropecten polyacanthus

The lateral rows of spines are typical. It lives buried in the sand during the day. As a post active hunter it eats mussels and molluscs living in the sand. Found in the Red Sea to Oman.

Fotos Johann Vifian

Quellen:          Korallenriffführer und Riffführer Rotes Meer / Wikipedia