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Anthias anthias

life science Maturity 5-7 Next article →

The swallowtail sea perch is a fascinating marine fish. Scientists call this species *Anthias anthias*. It belongs to the family Anthiadidae. These ray-finned fish are well known for their vibrant colors. They play an important role in reef ecosystems. Many people also find them in the marine aquarium trade. They are found in the Mediterranean Sea and the eastern Atlantic Ocean.

The physical body of *Anthias anthias* has several distinct features. It has a rather deep body shape. The standard length is about 2.5 times its depth. The dorsal fin contains 10 spines and 15 soft rays. The third spine on this fin is especially long. The anal fin has three spines and seven soft rays. The caudal fin, or tail fin, has asymmetrical, pointed lobes. The lower lobe is longer than the upper lobe.

Coloration is another way to identify this species. Their colors range from pink to deep red. They possess three yellow lines on the sides of their heads. Sometimes, they show brown blotches along their backs. Their pelvic fins are usually yellow. However, these fins turn red when the males are breeding. They also have a complete lateral line. This line contains 36 to 39 large scales.

These fish follow a unique biological process called protogynous hermaphroditism. This means they can change their sex during their lifetime. Every individual hatches as a female. If a male in a group dies, a large female changes. She becomes a new male to lead the group. This transformation takes about two weeks to complete. The change involves more than just the gonads. The fish also changes in size, shape, and color.

Social structures within a school are very specific. Most members of a group remain female throughout their lives. Even a large school might only contain a few males. Interestingly, this sex change can sometimes go in reverse. If there are too many males in a social group, some can revert. They change from males back into females. This helps the group maintain a healthy balance.

*Anthias anthias* has a complex history in scientific study. Carolus Linnaeus first formally described the species in 1758. He named it *Labrus anthius* in the tenth edition of *Systema Naturae*. He identified southern Europe as the type locality. Later, Marcus Elieser Bloch created the genus *Anthias*. He used *Anthias sacer* as the type species for that genus. However, that name is now considered a synonym of Linnaeus's original name. The name *Anthias* comes from a Greek word for fish.

Their habitat and feeding habits are also very interesting. They live at depths ranging from 5 to 60 meters. They prefer to live among rocks and corals. During the day, they hide inside caves for safety. At night, they emerge to hunt for food. They eat zooplankton, small crustacea, and smaller fishes. They have even been observed to feed cooperatively. Some fish will herd the prey, like shrimp. Other fish then eat the prey. They switch roles so that everyone can eat.

The distribution of this species is quite widespread. In the eastern Atlantic, they live from Portugal south to Angola. They also reach northern Namibia. They are found around the Azores and Madeira. They also live in the Canary Islands and Cape Verde Islands. They inhabit the islands in the Gulf of Guinea. In the Mediterranean, they are very common. They have been recorded in the Canakkale Strait. However, they have not been found in the Black Sea.

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