a tendency to develop black pigmentation, common in many species of anemonefish
unusual increase in melanin, a specimen exhibiting melanism is referred to as melanistic.
Melanism is the color of an animal when its skin contains an excess of color pigment compared to the general population. Melanistic individuals are usually much darker, and may be even completely black. Melanism may result from the over-expression or duplication of genes that are responsible for producing color pigment. A common protein that serves as a color pigment is melatonin. Definition link: melanism
Blackness, the opposite of albinism
To have a large amount of dark pigmentation caused by a high concentration of melanin. Melanism is not uncommon in older adult male Red Eared Sliders.
The preponderance of blackness.
The opposite of albinism; an undue development of colouring material in the skin and its appendages. 121
unusual darkening of normal pigmentation due to increased melanin.
The deposition of melanin pigment in a structure, rendering that structure blackish. In moths, generally refers to a blackening of the wings that is controlled by a single gene (as opposed to polygenic "darkening").
Melanism is an increased amount of black or nearly black pigmentation (as of skin, feathers, or hair) of an individual or kind of organism. More technically, it refers to a phenotype in which the pigmentation of an organism is entirely, or nearly entirely, expressed. A synonym for this condition used in the context of human disease is melanosis.