Monday, May 4, 2015


There are a number of marine fishes that are renowned for their aggressive tendencies. One of these is the Sohal surgeonfish (Acanthurus sohal). This is truly a “bad boy” of the reef! The Sohal shown in this video (which was named Kevin by one of the patients at this rehab facility) was kept in a 700-gallon aquarium. It regularly dashed around your hand as you attempted to clean the aquarium, but it never brought its caudal peduncle spine to bear. However, it would nip your hand and forearms! Not only did it let the Reef Tectonics technician know that it was boss, it had a particular disdain for the magnet we used to clean the aquarium - as you will see if you watch this video. (Note: that this video was taken after the surgeonfish had calmed down a little bit - his initial attacks were even more savage!).  
The Sohal surgeonfish is found in the Red Sea and Arabian Gulf. This is also one of the larger members of the clan, attaining a maximum length of about 16 inches. It is white overall with black stripes down the sides and on the top of the head. The caudal spine is red and a yellow patch develops under the pectoral fin as this fish grows.

The majestic Sohal surgeonfish exhibits a more elongate body, which is indicative of its more active lifestyle. The orange coloration on the caudal peduncle marks the venomous caudal peduncle spine.  
The Sohal Surgeon is the ecological equivalent of the lined surgeon (Acanthurus lineatus) from the Indo-Pacific. Like this species, the Sohal is found in shallow water in habitats exposed to excessive turbulence, like the outer tidal flats and on the edge of the reef crest. It is also highly territorial, evicting any food competitors from its territories. The caudal peduncle spines of this species are very large (like those of A. lineatus), and they are venomous - hence, they are very effective weapons.

Like its counterpart A. lineatus, the Sohal surgeonfish has a more elongate body, which may be related to greater levels of activity. As a result, it needs plenty of swimming room, hence adults must be kept in larger aquariums if they are going to be successfully acclimated to captivity (I would suggest a minimum of 180 gallons and preferably larger). The Sohal Surgeonfish will dash from one side of the tank to the other and chastise other fishes kept with it, especially other surgeonfishes and food competitors (this is especially true of those species with similar body shapes). The aquarist should be aware that it is not uncommon for this beast to kill its rivals with its large caudal spines in the confines of an aquarium. The individual shown in this video mortally wounded an angelfish we added to the tank in a matter of minutes! Before we could get the angelfish out, it had numerous lacerations.

 ©  Scott W. Michael- Reef Tectonics

 Reef Tectonics Aquarium Maintenance and Design - Lincoln, Omaha, Des Moines, Kansas City

No comments:

Post a Comment