Acanthuridae

Acanthuridae
Sohal surgeonfish, Acanthurus sohal
Scientific classification
Kingdom: Animalia
Phylum: Chordata
Class: Actinopterygii
Order: Perciformes
Suborder: Acanthuroidei
Family: Acanthuridae
Genera

Acanthurus
Ctenochaetus
Naso (unicornfishes)
Paracanthurus
Prionurus
Zebrasoma

Acanthuridae ("thorn tail") is the family of surgeonfishes, tangs, and unicornfishes. The family includes about 80 species in six genera, all of which are marine fish living in tropical seas, usually around coral reefs. Many of the species are brightly colored and popular for aquaria.

The distinctive characteristic of the family is the spines, one or more on either side of the tail, which are dangerously sharp. The dorsal, anal and caudal fins are large, extending for most of the length of the body. The small mouths have a single row of teeth used for grazing on algae.[1]

Surgeonfishes sometimes feed as solitary individuals, but they also often travel and feed in schools. It has been suggested that feeding in schools is a mechanism for overwhelming the highly aggressive defense responses of small territorial damselfishes that vigorously guard small patches of algae on coral reefs.[2]

Most species are relatively small and have a maximum length of 15–40 cm (6–16 in), but some members of the genus Acanthurus, some members of the genus Prionurus, and most members of the genus Naso can grow larger, with the whitemargin unicornfish (N. annulatus), the largest species in the family, reaching a length of up to a metre (3,3 ft). These fishes can grow quickly in aquariums so it is advisable to check the average growth size and suitability before adding to a marine aquarium.

Contents

Species

Timeline of genera


Etymology and taxonomic history

The name of the family is derived from the Greek words akantha and oura, which loosely translate to "thorn" and "tail", respectively. This refers to the distinguishing characteristic of the family, the "scalpel" found each member's caudal peduncle.[1]

In the early 1900s, the family was called Hepatidae.[3]

In the aquarium

Tangs are very sensitive to disease in the home aquarium. However if the tang is fed enough algae and the aquarium is properly maintained disease should not be a problem. It is usually necessary to quarantine the animals for a period before introducing them to the aquarium.

Adults range from 15–40 cm (6-15 in.) in length and most grow quickly even in aquariums. When considering a tang for an aquarium it is important to consider the size to which these fish can grow. Larger species such as the popular Pacific Blue tang surgeonfish (of Finding Nemo fame), Naso or lipstick tang, clown and sohal tangs can grow to 40 cm (15 in.) and require swimming room and hiding places.

Many also suggest adding aggressive tangs to the aquarium last as they are territorial and may fight and possibly kill other fish.

Tangs primarily graze on macroalgae, such as caulerpa and gracilias, although they have been observed in an aquarium setting to eat meat-based fish foods. A popular technique for aquarists, is to grow macroalgae in a sump or refugium. This technique not only is economically beneficial, but serves to promote enhanced water quality through nitrate absorption. The growth of the algae can then be controlled by feeding it to the tang.

References

  1. ^ a b Froese, Rainer, and Daniel Pauly, eds. (2007). "Acanthuridae" in FishBase. February 2007 version.
  2. ^ Mixed schooling and its possible significance in a tropical western Atlantic parrotfish and surgeonfish. WS Alevizon, Copeia 1976:797-798.
  3. ^ Seale, Alvin (1909). "New Species of Philippine Fishes". Philippine Journal of Science (Bureau of Science in Manila) 4 (6).