In the early days of freshwater ornamental fish breeding, one of the first mutations that consistently appeared in high profile species like angelfish and discus was a half black trait that originated at the tail. It seems like this mutation is not unique to fish from lakes and rivers as two examples of half black surgeonfish just hit our radar thanks to RVS Fishworld.
Coming from two different oceans the two half black tangs include one gem tang from Madagascar, and the other being a half black regal blue tang from Papua New Guinea. We’ve seen a decent number of unusual regal blue tangs, usually with someextra black colorationeither being masked,几乎所有的黑色,或者介于两者之间的半黑色君威tang follows a trend of aberration forParacanthurus hepatusand is probably only the latest in more that will arise in the future.
The unusualZebrasoma gemmatumwith its round body outline really closely resembles the half black freshwater angelfish and discus from the middle of last century with even the tail being darker, but not completely black, and is one of the rare morphs of this really iconic west Indian Ocean species. It might not be a showstopping mutation but since gem tangs are very conservative in their appearance, only occasionally appearing with abar code color pattern, it’s noteworthy to see an unusual example in a sea of this cookie-cutter species.