Species group: Tangs and Surgeonfish
Other common names: Mimic Surgeon; Mimic Lemon Peel Tang; Chocolate Tang; Mimic Tang; Mimic Surgeonfish
Scientific name: Acanthurus pyroferus
The Chocolate Surgeonfish is moderately easy to care for. These Surgeonfish are continuous feeders and are primarily herbivorous. In its juvenile phase, it mimics Angelfish and one reason for this could be that this disguise provides protection while their caudal peduncle spine is immature. Angelfish are rarely preyed on hence the convenience of disguise is useful. Chocolate Surgeonfish have a diet similar to Damselfish that prey on Surgeonfish. These Surgeonfish also have a much more restricted diet than that of the Angelfish. The Angelfish are subjected to fewer attacks by the Damselfish as opposed to the Surgeonfish. This mimicry deceives the Damselfish so the Surgeonfish suffer fewer attacks and it allows the Surgeonfish to feed more freely in the Damselfish's defended areas.
The Chocolate Surgeonfish is considered a good choice for the home aquarium because they do not get as large as many others in the same genus. Juvenile Surgeonfish find it easy to acclimate themselves to the tank but adults are reportedly very hard to acclimate. Once it is acclimated to its environment, it is quite hardy, adaptable to a wide variety of foods, and can handle a wide range of water parameters. The Chocolate Surgeonfish is less susceptible to diseases, such as Marine Ich and Marine Velvet, compared to other species of Surgeonfish.
The Chocolate Surgeonfish has a disk-shaped body with a spine that is like a scalpel on either side of the caudal peduncle. In the juvenile stage, it can exhibit three different color patterns mimicking the Centropyge species including the Eibl’s Angelfish, Lemonpeel Angelfish, and Herald’s Angelfish. It may have a yellow oval body and blue highlights around the eyes and gill covers, mimicking the Lemonpeel Angelfish (Centropyge flavissimus). While mimicking the Eibl’s Angelfish (Centropyge eiblii), the juvenile Chocolate Surgeonfish has a cream colored body with vertical orange stripes and a black tail. When mimicking the Herald's Angelfish (C. heraldi), it is completely yellow in color. While imitating the Pearlscale Angelfish (C. vrolikii), it will have a body that is light towards the front, very dark on the back and on the fins, with grayish spotting. In the juvenile stage, the caudal fin is rounded. The mature Chocolate Surgeonfish’s body darkens to a tan color with red highlights around the eyes and pectoral fins. The dorsal, anal, and caudal fins have a green hue but are tipped with the tan body color. The mature Chocolate Surgeonfish can also have a yellow to dark brown or purplish black body with an orange diffused patch at the edge of the gill opening, just above the pectoral fin base. The adult fish also has a black band which begins from the upper end of the gill opening arcing down below the chin. A white line is also seen encircling the chin. The fish has blackish lips. There is a narrow black margin on the caudal spine socket. Color changes in juvenile and adult stages. Juveniles too have different color variations like yellow, blue, cream, orange, black, and grey. Adults can have tan, red, green, yellow, dark brown, purplish black, orange, and white colors.
They do not harm corals or invertebrates. They can be kept with a variety of tankmates but they will be aggressive towards other Tangs, Surgeonfish, and fish with similar body shapes and color. They can be territorial, especially with new additions to their aquarium. Surgeonfish can handle themselves well with more aggressive fish like Triggers, large Wrasses, and Puffers.
The Chocolate Surgeonfish can be housed in a 75-gallon or larger aquarium. Surgeonfish are quick agile swimmers and need plenty of swimming room. They also require plenty of rocks and corals to hide in and to wedge themselves into at night for sleeping. They like lots of water turbulence as opposed to a placid aquarium. They thrive with good water movement as they need lot of oxygen, and they enjoy water rushing over their gills at times.
However, they graze on algae and are, therefore, useful in a reef environment. Normal lighting conditions are acceptable. If bright lighting is used, some areas must be kept dim. Surgeonfish are susceptible to bacteria resulting from organic buildup which deteriorates water quality. Vigorous filtration, protein skimming, and regular small water changes are, therefore, very essential.