ABERRANT Bristletooth Tang - (Ctenochaetus sp,)

Care Level - Moderate

Temperament- Semi-aggressive

Reef Safe - Yes

Max Size - 7"

Min. Tank Size - 100 gallon

Aberrant Tangs are one of the most striking and unique fishes an aquarist can obtain, and for that reason they demand extremely high prices when they are rarely offered for sale. For our purposes, “aberrant” refers to coloration or patterns that are significantly different from the normal coloration of the fish. This can be as simple as a small blemish or be a complete mess of koi-like coloration. Later in this article I’ll describe a case of multiple Tangs developing aberrant coloration in captivity. This on its own is odd enough, but what makes this even stranger is that the only individuals affected belong to the sister genera Acanthurus and Ctenochaetus which seem to exhibit aberrant coloration only very rarely in the wild. Before I get into that, an overview of aberrations in the family Acanthuridae will help to give us some context for what we are seeing.

Photo by Richard Ross.

There are many examples of aberrant individuals among the Surgeonfishes, or Tangs. One of the first widely publicized examples of an aberrant Tang was a Scopas Tang (Zebrasoma scopas) kept by master aquarist Greg Schiemer. This so-called “Tricolor Tang” had a unique and blotchy color pattern unlike the typical Scopas Tang. When it was purchased it was mostly yellow with a white tail. Over time in captivity the front half of the fish gradually developed typical Scopas Tang coloration, but the white tail and yellow back remained (Schiemer, 2002). There are now multiple examples of Tricolor Scopas Tangs collected from the wild which show varying degrees of irregular yellow, white, and pale brown blotches (Carvallo, 2013). Aberrations in the Scopas Tang are not a localized phenomenon; multiple examples have been collected in East Africa, the Andaman Islands, and Vanuatu (Carvallo, 2013, Ho, 2013, Norton, 2013) and probably occur throughout the species’ range. There are also many examples of aberrant individuals in the closely related Yellow Tang (Zebrasoma flavescens). Yellow Tang aberrations are generally all characterized by having irregular white patches that may cover some or all of the body (Adams, 2011). These aberrations currently appear to be stable and do not revert back to wild coloration in captivity. There is one known photograph of a similar aberration in the Purple Tang (Zebrasoma xanthurum) with white and yellow blotches on a regularly purple body (Adams, 2011), but it is unknown if this fish’s condition is stable in captivity.