Acanthurus gahhm
Source: JJPhoto.dk

Facts

Latin name Acanthurus gahhm - (Forsskål, 1775)
Common name Black surgeonfish
Family Acanthuridae - Acanthurus
Origin East Indian Ocean, West Indian Ocean, Australia, Indonesia, Central/West Pacific
Max length 40.0 cm (15.7")

As aquarium fish

Minimum volume 2000 l (528 gal)
Hardiness Average
Suitable for aquarium Suitable with care
Reef safe Always reef safe
Aggressiveness Might be aggressive towards similar species

Food

Mostly
  • Small crustaceans (Krill, mysis, artemia...)
Recommended
  • Microalgea (Eg. spirulina)
  • Macroalgea (Eg. seaweed / nori)

Well established aquarium with algae

These fish should be kept in a well run aquarium where they can "graze" algae from rocks and stones.

If there are insufficient algae on the rocks, it is important to feed more frequently and supplement with algae rich food e.g. Spirulina. 

Frequent feeding

This species requires frequent feeding, at least a couple of times per day.

Requires plenty of space for swimming.

This species revels in swimming and requires an aquarium with ample space.

Algae Eaters

Even though these fish enjoy a diverse type of frozen foods, it is imperative that its primary food, is algae based, thus ensuring that the fish`s immune system remains healthy.

This can, for example, be plant based fish flakes, Nori seaweed or similar.

Hiding places

This species requires places to hide, especially when newly introduced into the aquarium.

Description

These fish are difficult to distinguish from Acanthurus nigrofuscus, but A. nigrofuscus has a black marking by the scalpel.

Genus description (Acanthurus)

Some species in the Acanthurus genus mimic various Angelfish as juvenile, since predatory fish know that small Angelfish are hard to catch. They are therefore difficult to identify from a picture of adult fish.

Acanthurus species often place higher demands on: tank size, surroundings and water quality, than fish in the genus Zebrasoma.

Family description (Acanthuridae)

Surgeonfish (Acanthuridae) live primarily of different types of algae, making it a popular choice for coral aquariums, as they help to keep the aquarium algae free.

Most Surgeonfish have a scalpel by the caudal fin, used to defend themselves. It can cause some deep lacerations, so pay attention if the fish start to fight and when handling the fish.

When in the aquarium, they will spend most of their time swimming around and nibbling the algae from the stones. Surgeonfish will rarely irritate corals or invertebrates. Large Palettes/Blue tangs can be an exception.

The Surgeonfish are not typically aggressive towards other types of fish. If more Surgeonfish are added to the aquarium, they will establish a hierarchy. It is best to add the most aggressive species last and to ensure that there are sufficient hiding places, as they prefer to have their own individual sleeping area.

If multiple aggressive species are added to the same aquarium, one runs the risk of one of them dying due to stress. One must therefore be cautious about adding multiple Acanthurus species or Zebrasoma xanthurum into the same aquarium. A combination of the different genera will normally get along well, although the more aggressive species can still be challenging.

FishBase

Aquarium trade Yes
Distribution Western Indian Ocean: endemic to the Red Sea and the Gulf of Aden.
English common names Black surgeonfish
Danish common names Sort kirurgfisk

References and further reading

About references

Bob Fenner. The Tangs, Surgeons, Doctorfishes, of the Genus Acanthurus Part 1, Part 2 - Wet Web Media - (English)
Bob Fenner. The "Bad", Unknown and Just Too Dang Big Tangs, Surgeons, Doctorfishes, of the Genus Acanthurus - Wet Web Media - (English)

James W. Fatherree. 2009. Aquarium Fish: Surgeonfishes, A.K.A. the Tangs - Advanced Aquarist - (English)
Bob Fenner. Surgeons, Tangs and Doctorfishes, Family Acanthuridae - Wet Web Media - (English)
2013. Kirurgfisk - Saltvandswiki - (Danish)

Froese, R. and D. Pauly. Editors. 2014. FishBase. World Wide Web electronic publication. www.fishbase.org, version (08/2014).

Tags

herbivore, algae eater, surgeon tang
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