September 7, 2011 
Did you know that fishes exhibit different colors at night? The color pigment cells (chromatophores) are more spaced out at night, giving vibrant fish a dull look. They do this to conserve energy, afterall, maintaining color in the absence of light is useless. The same thing can happen to a fish in the daytime if it is stressed out. Of course, it’s often harder to ID them at night when a fish changes it’s colors.
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- Day Colors, Sea Hare
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- Sea Hare
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- Day Colors, Speckled Scorpionfish
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- Scorpionfish?
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- Scorpionfish?
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- Day Colors, Raccoon Butterflyfish
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- Raccoon Butterflyfish
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- Day Colors, Iridecent Cardinalfish
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- Iridescent Cardinalfish
Reef Watch Waikīkī 
As you mentioned, fish also change color during the day. To me, the change in white saddle goatfish is rather dramatic (from pink to gray), though I haven’t captured any photos of the “before” and “after.”
Hey Cassidy – can you add comparison photos with the day-time coloration (where possible)? Thanks!
I’ve just posted some day time colors of the same animals 🙂