The moorish idol is a fish so widespread, iconic and recognizable that its black, white, & yellow stripes have been an integral part of marine artwork for over a hundred years. It’s the conservative nature of how moorish idols look that makes them such a poster fish for tropical marine fish so it’s with great surprise when we learned that Japan’s AquaStar received a specimen of Zanclus cornutus missing its typically yellow coloration over most of its body.
Except for a small patch across the mouth this monochrome moorish idol has ‘lost’ all of the pastel lemon yellow coloration that typically adds a dash of pop between its bold black markings. While the appearance of moorish idols might be more reminiscent of a classic butterflyfish both in color and in shape the single species in the Zanclus genus is actually more closely related to surgeonfish, actively grazing on the reef like we expect from tangs and such.
Interestingly, this is the first time we’ve seen a specimen of monochromatic moorish idol in the aquarium world but four years ago we shared a video of a similar fish that was documented in the wild. We don’t doubt that this unique moorish idol will be well cared for in a saltwater aquarium environment but what we don’t know is whether the color is persistent or whether the fish will revert to normal coloration over time. Without its splash of yellow this black and white Idol really reminds us of the beloved freshwater altum angelfish but with only one known specimen this unique fish is bound to end up in the collection a very affluent collector.