Ocean Watch

"Is there such a thing as an albino fish?" That question comes from Mollie, a reader who spotted a small white fish shaped like a yellow tang. "Its eyes are dark, and it has a white spot on its tail spine, sort of white on white," writes Mollie. "Every month when we go back, I look him up and there he is, same locale, hanging around the yellow tangs. ... How rare is this?"

Jack Randall writes in his book "Surgeonfishes of Hawaii and the World" (tangs are surgeonfish) that albino yellow tangs "have been seen" in Hawaiian waters.

How rare are they? Based on the warning I received from a Waikiki Aquarium biologist, I think it's safe to call the white fish rare. "Don't mention its location," she said. "A tropical fish collector will take him."

Mollie is lucky to see Haole Boy (her nickname for the fish) over and over because albino fish live on the edge. Besides the chance of being kidnapped, a white splotch amid a swirl of yellow is like a neon sign to passing predators.

Albinism, as it's called, is an inherited metabolic disorder. Its chief feature is lack of melanin, the substance in plant and animal cells that produces color.

The condition occurs when two recessive genes combine and block an enzyme essential in the manufacture of melanin. About 1 in 17,000 people have albinism.

Countless animal species also have it. White rabbits, for instance, are albinos. It's a lack of melanin that produces their white fur and pink eyes.

Pink is often featured in albinos because underlying blood vessels show through transparent skin and eyes.

In my search for information about albino fish, I learned that people commonly breed albino fish for the freshwater aquarium trade. Like other animals, and people, too, some of these fish bear traces of color here and there, meaning their melanin production is abnormal but not entirely absent. This is likely true of Haole Boy, too, since his eyes are black.

(You can't tell the sex of a surgeonfish by sight, but that's OK. In calling it a male, Mollie has a 50 percent chance of being right.)

When you start looking into albino animals, there's a wealth of good stories.

Take Persil, an albino squirrel in Britain. People discovered him when he got knocked out of a tree by a soccer ball. He's fine.

Then there's the albino lizard, exposed to the world because it can't blend into its background, and a frustrated albino peacock ignored by all the peahens.

Besides standing out in a crowd, life for an albino can be hard because melanin provides some protection from the sun. Albinos of all species are at high risk for skin cancer and have an aversion to light because too much of it enters the eyes.

People with complete albinism often wear dark glasses.

Albino genes travel through the world's oceans. I found photos of an albino ray, sea lion, Port Jackson shark and humpback whale. And, of course, there's the famous if mythical white sperm whale, Moby Dick.

Chubs, or nenue, also produce the occasional albino here in Hawaii.

The waters around Easter Island, Randall told me, are full of white nenue.

Yellow tangs are the most collected aquarium fish in Hawaii, and a rare white one would be highly coveted. But don't worry, Mollie.

Haole Boy's hideout is safe with me.