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Diel colour changes in the neon tetra Paracheirodon innesi

1983; Springer Nature (Netherlands); Linguagem: Inglês

10.1007/978-94-009-7296-4_10

0924-5316

J. N. Lythgoe, Julia Shand,

Ichthyology and Marine Biology

SynopsisIn the daytime the neon tetra Paracheirodon innesi has an iridescent blue-green lateral stripe and a red ventral area. At night the lateral stripe becomes deep violet and the ventral area fades. The iridescent colours are produced by constructive interference from regular stacks of thin reflecting plates in dermal iridophores. Colour changes of the reflected light result from changes in the spacing of the plates which is caused by the direct action of light on the skin, and also by emotional arousal. Fading in the red areas is due to the migration of pigment granules within the chromatophore. On the basis of existing measurements of spectral transmission of Amazon waters, where the fish are thought to live in nature, and microspectro-photometric measurements of visual pigments in the visual cells it is concluded that neon and cardinal tetras are conspicuous in the daytime when they are active, and camouflaged at night when they are inactive.