- Submitted by dvross
These are common questions for many new fish keepers and can be downright confusing at times. While the terminology can be disputed, the basic theory behind these terms is fairly clear-cut. The purpose of this article will be to clarify each of these terms so that you will be able to recognize the various color morphs and have a basic understanding of what causes them.
In reality a “True” albino is characteristically described as being devoid of all pigment producing chromatophores (think of a white albino rabbit with pink eyes.) However there are varying degrees of albinism which are characterized by a lack, or diminution, of certain chromatophores. These chromatophores, which are discussed in greater detail below, are responsible for creating the various colors.
Among hobbyists, different terminology has been adopted to describe certain ‘typical’ characterizations of albinism. It is this interchangeable jargon that can cause a great deal of confusion. Fortunately there is a, to a degree, a level of agreement between aquarists, bird keepers and herpetologists on the terms used to describe the many color morphs which represent the varying degrees of albinism.
Albino is the widely accepted condition of albinism which is characterized by an absence of any dark colored pigments such as black, brown, blue, or green.
Albino describes the condition whereby the fish displays a lack of black and brown pigments (melanin). This does not preclude the fish from having other colors such as reds, yellows and blues. On the contrary, this is ‘usually’ the case. A true albino, as described above, is extremely rare.
Lutino is a word which describes another typical degree of albinism characterized by low quantity of black and brown pigment (melanin). Usually any black and brown colorations present, are located on the fins as well as the eyes.
Various hues are made possible by the combinations of different layers of chromatophores. Cells carrying more than one pigment are called compound chromatophores. There are five types of chromatophores which produce the colors you see in fish and are characterized by the color they carry. In addition there is another component called the Iridophore. It is responsible for producing the reflective sheen you see on fish. The Iridophores are concentrated in whitish and silvery belly surfaces, and are responsible for the metallic glitter on the side skin of many fishes. The reflectivity of iridophores is due to the presence of light-reflecting platelets of guanine within the cells
Erythrophores are red chromatophores containing carotenoids and pteridines which produce the reddish pigments.
Melanophores are dark chromatophores containing melanin and produce the black and brown pigments.
Xanthophores are yellow chromatophores which contain carotenoids and produce the yellow pigments.
Cyanophores produce blue pigments but their chemical makeup is not fully known at this time.
Leucophores are light-scattering chromatophores which look whitish when illuminated by incident light. They usually sit underneath melanophores and produce a melanophore-leucophore complex
Fish are capable of producing some pigments, but others must be supplied in the diet. For example, they cannot produce carotenoids naturally. They accumulate carotenoids from their diet and transfer them into pigment cells to produce red, yellow, and orange colors. The intensity of the pigment is reliant on the quantity and types of carotenoids supplied in their food. The carotenoid pigment found in most marine invertebrates is astaxanthin. Another pigment that is derived from a food source is phycocyanin. This pigment is blue and is readily found in blue-green algae. Additionally, the ability of fish to store pigments they have acquired from their diet will greatly affect their appearance.