acanthurus pyrofreus

Acanthurus pyrofreus is a species of surgeonfish that mimics the lemonpeel angel, seen on the facing page.

Centropyge flavissimus

This is the real lemonpeel angel, Centropyge flavissimus.

Q: A local pet store, just outside Seattle, had a yellow fish with blue markings called a mimic tang. After looking through several books the only fish I found that resembles it is the real lemonpeel angel, Centropyge flavissmus. Is this the fish it “mimics?” I have never heard of fish mimicking each other. What is the reason behind this and are there any other fish that “copy” one another? The local library could give me no information, so I would appreciate any you can give me. Lanny Palmer, Washington.

A: The fish you saw is probably Acanthurus pyroferus, a species of surgeonfish that does mimic the lemonpeel angel. A tang that looks like an angelfish, but isn’t. This tang is usually collected in Samoa, along with the much more common lemonpeel angel. In Indonesia, this species copies the candy angel, Centropyge eibli, a species with a completely different color pattern. The front of the body is light grey with an orange throat area, orange rims around the eyes and numerous vertical reddish pinstripes. This color pattern gradually changes to a sooty black at the base of the tail with the black tail being edged in a light blue or white.

Unfortunately, both variations of A. pyroferus lose their attractive juvenile coloration at about 5 inches and assume a much more subdued adult color pattern. Adults have a darkly marked face and throat area with a pale yellow body and and dark brown fins. In nature, maximum size is 8 inches but aquarium specimens rarely reach 7 inches. Acanthurus chronixis is another species of surgeonfish that mimics two different angelfish. In the Philippines, A. chronixis copies the yellow angel, Centropyge herald, while in Indonesia, this same species mimics the half black angel. Centropyge vrolikt. I have never seen the adult coloration of this species but I am sure that there is a distinct adult color pattern It is said to reach a length of 7.5 inches in nature, but I have never seen an aquarium specimen over 4 inches. Both species of mimic tang are very easy to keep and are an excellent choice for beginners or advanced hobbyists.

In fact, I have found that they are much easier to keep than the angelfish they mimic. Like all tangs, these fish are decidedly herbivorous. A vegetable flake, such as Tetra Conditioning Food or OSI Spirulina Flake are excellent staple foods for tangs. This should be supplemented by frozen foods such as Ocean Nutrition Formula Two or Lifeline Herbivore and green vegetables such as romaine lettuce. Frequent partial water changes, good filtration (including an ultraviolet sterilizer), and a diet rich in vegetable matter make it easy to maintain the good water quality all surgeonfish need to thrive. Their dietary requirements, relatively small adult size and hardy nature make them an ideal candidate for an invertebrate aquarium. They will graze continuously on the algae and never bother live corals. I am sure that there are numerous examples of mimicry in saltwater fish but there is only one example that is commonly seen in the aquarium trade.

There is a species of blenny that appears as a contaminant in shipments of cleaner wrasses. The color pattern is so similar that many wholesalers have a hard time telling the benevolent cleant wrap, Labroides dimidiatus from the aptly named sabertooth blenny, Aspidontus taeniatus. This blenny mimics not only the color pattern but also the jerky swimming motion of the cleaner wrasse. It will also open a “cleaning station” like a cleaner wrasse. These cleaning stations are small territories that cleaner wrasses hold that large fish frequent looking to Yet parasites removed. I guess that a large angelfish figures that if it looks and stems like a cleaner wrasse it has to be a leaner wrasse. The blenny gives the appropriate cleaning display for the larger fish and instead of picking the parasites off, it grabs a mouthful of scales and flesh. I discovered my first sabertooth blenny I removing dollops of flesh from a large emperor angelfish in a wholesalers tank. Needless to say the sabertooth blenny is an oddity that is best left in the ocean.

There are cases where mimicry obviously works to a fish’s advantage. The sabertooth blenny uses its similar color and behavior to be able to feed itself. The juvenile color pattern of the pinnatus batfish, Platax pinnatus, is very similar to a poisonous flatworm. This mimcry is used as protection against predators, a tactic also used in the insect world. There are many more that are quite baffling. Why would different species of freshwater catfish mimic one another? Or, for that matter, why would a tang, a fish that schools in the ocean, give up safety in numbers to mimic an angelfish, a fish that lives by itself and is constantly defending territory on a reef? Since nature never makes mistakes it is obvious that there is something we are missing. It is through careful observations, in the wild and in the aquarium, that these mysteries are eventually solved. An enthusiastic hobbyist can be just as observant as a Ph.D, so don’t be shy about sharing your opinions and observations.