Parrotfish are closely related to the wrasse family. Like these, they have a circumtropical distribution.
Their range is the entire Indo-Pacific, including the Red Sea and East Africa to the Line Islands and Samoa and beyond. Exact information on this can be found with the individually described species.
There are a total of 8 genera with about 70 species.
They live in the coral reef at 1 to 30 m depth in the fringing zones during the day, but rest in caves or shallow sandy lagoons at night. Juveniles are found in seagrass beds within lagoons, while adults are more commonly found in outer lagoons and seaward reefs. This species is gregarious and usually found in small groups, but group sizes can be quite large on seaward and clear reefs of the outer lagoon. They sleep in large groups, making them particularly vulnerable to nocturnal exploitation by spear fishers and net fishermen.
Actually, all species are algae eaters. With their powerful "parrot's beak" they scrape the algae from the stones. This is very hard and leaves visible marks on the stones.
Certainly, they also take microscopically the smallest organisms with them by scraping them off.
Many species have a reputation for eating hard corals, although it is still not certain whether they are interested in the tissue or the zooxanthellae.
According to gastric studies, 80% of the contents of parrotfish consists of a finely ground mixture of limestone, sand, and detritus (Hobson 1974).
Species of the genera Sparisoma, Scarus, and Bump head parrotfish (Bolbometopon muricatum) are known to feed primarily on live coral. These can excrete enormous amounts of digested coral, which comes out as sand. This is where a large part of our sea sand comes from. Other species feed on seaweed and various algae. Shellfish, moss animals and bristle worms are also eaten as additional food. Overall, they are not a threat to the corals.
This different feeding behavior also ensures a balance between corals and algae in the reef and is a basis for the development of new corals.
Most parrotfish are beautifully colored, but until then they go through several colorations. So it's sometimes a guessing game to assign it to a species. Parrotfish are real eye-catchers thanks to their bright colors. Especially since active females can still transform into males and are then said to be even more beautiful than the actual males.
Due to their gnawing on hard corals and the size to be expected, these fish should only be kept in large, non-hard coral enclosures, as alluring as their beauty is.
The parrotfish spend the night in a slime cocoon with a horizontal flow.
Within the life cycle, parrotfish go through three different phases, which are visible through different color stages:
1st phase, the juvenile phase, consists of sexually immature adolescents with a
characteristic gray color.
2nd phase, is referred to as the initial phase (initial phase) and consists of
sexually mature males and females.
3. The terminal phase consists only of mature adult males.
This also results in a very complex reproductive system.
They live in a harem group, with a single male terminal being dominant in a group of females. This dominant male will mate with the females in the group and harm other male competitors.
The species is diandrous, meaning the population includes primary and secondary males. A primary male was born with this sex. However, a secondary male is a female. That can become male if
the dominant male dies. Its death signals the largest female of the initial stage that she is undergoing morphological and behavioral changes and turning into a male.
Sneak spawning can also occur, with some early stage males disguising themselves as females to enter the harem.
At peak spawning, they release a plume of germ cells to prevent fertilization by terminal stage males.
They are particularly adept at this process as they have larger testicles than the terminal phase male and thus produce more gametes than the latter, increasing their chance of fertilizing the female's ova.
