Aberrant scopas tangs, also known as koi tangs and tricolor tangs are very unique form of the Zebrasoma scopas surgeonfish. A normal scopas tang is a fairly easy fish to overlook with a spade shaped body outline that has a basic color gradient that ranges from brown to black.
However, every now and then a scopas tang is collected with a very unusual color pattern. No one really knows why some scopas tangs can show a trio of colors, or have their normal color suffused with a bluish green, usually in an irregular pattern that behaves differently on the fins than on the body of these fish.
We’ve been covering the appearance of these tricolor and aberrant scopas tangs for years, and there appears to be a preponderance of these from the Indian Ocean. More recently however, it seems like a hotspot of these aberrant scopas tangs have been discovered south west of Java Indonesia, and we’re starting to see these specimens pop up at aquarium shops all over the globe.
Naturally, suppliers of the koi and aberrant scopas tangs are rather vague about the precise location of their honeypot for the unusual and highly coveted scopas tangs. However we find it rather interesting that the new collection area is in the vicinity of Christmas Island, home of the Coco-peel angelfish and a known hotspot of reef fish hybridization.
It’s hard to say for certain what is causing the very unusual appearance of these scopas tangs; perhaps there’s some form of unstable genetics in these populations, it’s probably not vitiligo which usually destroys the color cells in the skin. The only real common denominator of these aberrant scopas tangs, is that apart from their collecting location, the koi scopas are all rather large for scopas tangs, and perhaps there’s a very bizarre form of sexual coloration at play with these fish.
One marine aquarium shop in particular, Southwest Marines in the UK has always had a ‘specialty’ of procuring the unusual variants of scopas tangs. This shop was the first place where we ever saw a really high grade tricolor scopas tang with patches of white, yellow and dark greenish brown.
As attractive as these fish might seem, potential buyers of these eye-catching Zebrasoma specimens need to be aware that what you see is not necessarily what you are going to get. By now it is well known that these aberrant scopas tang have very fickle color and pattern which can change nearly on a day to day basis.
In the extreme example from Southwest Marines below, a stunning yellow scopas tang with just a hint of black patch on one side changed color rather dramatically. During the course of just a week, the body began to show peppering of black coloration all over the body. A couple weeks later the fish had basically transformed into an unrecognizable version of its former glory, again with just a hint of unusual color in its fins.
Some specimens will revert to a mostly normal colored scopas appearance, while others may develop color that is even more extreme. No one knows what to expect from these fish and their colors can continually change throughout their life. By and large though, most of these koi scopas tangs will develop a normalized body coloration with some degree of the aberrant color and pattern remaining on the head, fins and tail.