Scissortail sergeant

The **scissortail sergeant** or **striptailed damselfish** (_Abudefduf sexfasciatus_) is a large damselfish. It earns its name from the black-striped tail and sides, which are remind people of the insignia of a military Sergeant, being similar to those of the sergeant major damselfish. It grows to a length of about . Scissortail sergeants live on coral reefs at depths of up to  in tropical reaches, often living in a group surrounding a single head of coral. They are found on reefs in the Indo-Pacific region, including the Red Sea. This fish is popular in the aquarium trade. It is very aggressive and difficult to stay peaceful with other similar size fishes.
The fish feed upon the larvae of invertebrates, zooplankton, smaller fishes, crustaceans, and various species of algae. They are preyed upon by some members of the Labridae and Serranidae families. They lay their eggs in patches on a firm substrate and guard them vigorously till they hatch.

## Description

This fish is white. They have 5 vertical bands that are black. Two horizontal bands are present on the sides of their tail. This fish can grow up to  at maximum length.

### Parental care

Like some other fish species, male scissortail sergeants are in charge of parental care. Males are polygamous and will collect eggs from up to 12 females while females spawn with a male and then abandon their eggs. Male parental care is more common than female or biparental care in fish because territorial males are able to guard several clutches of eggs while at the same time attracting new mates.

Male scissortail sergeants undergo brood cycling, in which they switch between a mating phase and a parental phase. During the mating phase, males become gold in color and put on displays to attract egg-laying females. After two to three days in the mating phase, male scissortail sergeants will lose their gold color and transition into a four- to five-day parental phase. During the parental phase, males guard their eggs until they hatch. Filial cannibalism occurs during the parental phase.

### Female choice

In order to select the best quality males and maximize their offspring survival rate, females will pool their eggs with other females into a single male's territory and create a larger brood. Studies have shown that pooling to create larger broods serves to not only decrease predatory effects, but also increases paternal work on the eggs. Also, males with larger broods are less likely to cannibalize (eat) their broods. It has also been thought that egg pooling is a simple imitation tactic by which females confirm the quality of the male. By copying the spawning behavior of other females, females can minimize the search costs of finding a good mate.

### Filial cannibalism

Filial cannibalism, the act of eating one's own children, is common in territorial male fish. It occurs during the parental phase of brood cycling. Embryo mortality rates are generally attributed more to filial cannibalism than to other fish eating eggs because embryo predators are largely unsuccessful. Recent studies suggest that filial cannibalism, in fact, is an evolutionarily adaptive behavior. Baseline cannibalism is a result of males eating nonviable or damaged eggs, but males may cannibalize their current broods even more based on the costs and benefits of their parental investment. Raising offspring requires a large amount of energy

## References

- Status of Abudefduf sexfasciatus (Lacépède), a Pomacentrid Fish from the Indo-West Pacific (in Ichthyological Notes) Gerald R. Allen; Marie-Louise Bauchot; Martine Desoutter _Copeia_, Vol. 1978, **2**. (May 5, 1978), pp. 328–30.

## Other websites

- Fishes of Australia : _Abudefduf sexfasciatus_