Some fish are white because they lack the pigments, particularly carotenoids, that give other fish their color.
Here's a more detailed explanation:
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Carotenoids and Fish Color: Many fish get their coloration from pigments called carotenoids. These pigments, responsible for red, orange, and yellow hues, aren't produced by fish themselves. They obtain them through their diet, consuming algae, plankton, and other smaller animals that have already accumulated these pigments.
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Fat Content and Pigment Absorption: A crucial factor in determining a fish's color is its fat content. Carotenoids are fat-soluble, meaning they dissolve in fat. If a fish has a low fat content, it's less able to absorb and store these pigments from its food. This results in a paler, often white, flesh.
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Dietary Differences: Different diets contribute to varying pigmentation. Fish that consume a diet rich in carotenoids, and possess sufficient fat to absorb them, will likely have colored flesh (e.g., salmon). Conversely, fish that eat a diet lacking these pigments or struggle to absorb them due to low fat content tend to be white.
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Examples of White Fish: Cod, haddock, and flounder are examples of fish species often having white flesh due to lower fat content and/or dietary factors.
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Other Factors: While carotenoids are a primary factor, other pigments and genetic factors can also influence fish coloration. However, the relationship between fat content, carotenoid absorption, and white flesh is a significant contributor.
