What Causes Rare Colored Fish?

Fisheries Lunchtime Lesson

Have you ever caught a fish and thought, “well that looks a little different”? It is not uncommon to find fish of many colors in a state as diverse as Arkansas. However, it is quite uncommon to find a fish that lacks any color. What do you call these genetic anomalies?

Like humans, rare genetic occurrences can appear in fish that cause some pretty unique features. There are typically three types of genetic mutations that lead to these colorations, or lack thereof. The most well-known mutation is known as albinism. Albinism occur when the presence of a recessive gene becomes dominant within the DNA. This gene inhibits the production of skin color known as melanin. These fish appear white or pink, and have no pigment in their eyes that lead them to appear red or pink.

Often mistaken for fish with albinism are leucistic fish. Leucism occurs when the melanin producing gene is masked, but not eliminated. These fish are able to produce some melanin, including color in the eyes and skin/scales. Recently, District fisheries staff were sampling catfish on the Cache River and caught three variations of leucistic Blue Catfish (see images 1 – 3 below).

Image 1: Leucistic Blue Catfish that appears to have no color on the body but does have colored eyes.

Image 2: Leucistic Blue Catfish that has a white head, also known as a “piebald”.

Image 3: Leucistic Blue Catfish displaying a blotchy coloration.

The third type of genetic mutation is known as melanism. This simply means that the melanin producing gene works overtime, causing the animals to exhibit all the colors, giving them a dark or black coloration.

What is even more rare than catching a fish that has albinism, leucism, or melanism, is a fish that displays Xanthochromism. This very rare genetic anomaly is caused when the skin lakes the presence of darker pigments causing a yellow or golden coloration (see images 4 & 5 below). AGFC Fisheries Biologists relate catching a golden fish to being more rare than winning the lottery!

Image 4: A xanthochromatic Largemouth Bass caught on Beaver Lake in Spring 2021.

Image 5: A xanthochromatic Crappie caught on Lake Columbia in 2019.