Gouramiguy17

my shrimp are very colorful during the day but when I turn in their tank in the morning they are always gray then they slowly change back to red. Is it a defense mechanism? Why do they do that

Coffey5030

In a word, camouflage. Many animals can only see black white and the spectrum of gray in between. When the lights go dim color is useless. The shrimp uses chromatophores just below its exoskeleton to change its color to a neutral gray.