Common Colour Mutations.

[Aquamick]

Some common and natural (not induced by selective breeding) colour mutations in tropical freshwater fish:

Albinoism; The fish lacks pigmentation and is white/cream with pink/red eyes. The pink/red is actually blood in the capillaries of the eyes, and under the skin dermis. Albino fish are thought to be less hardy than other individuals. They often have eye problems and increased light sensitivity.
Examples; Corydoras Paleatus, Aeneus and the Oscar, Astronotus Ocellatus.

Melanism; the over production of black pigment melanin, leading to black or abnormally dark colouration. Fish exibiting melanism are more prone to tumours. One Melanistic form of aquarium fish is the black Angel, Pterophyllum Scalare.

Leucism; white, but pigmented, usually with normal colour eyes. Less common than albinoism.
Example; White Molly, and some wild Malawi Cichlids, Metriaclima Callainos being the most common.

Xanthism; yellow pigmented. The best known xanthic fish is probably the Severum, Heros Severos. Another cichlid, the Midas or Yellow Devil, Amphilophus Citrinellus, has a naturally occuring xanthic morph.

Erythism; red or orange pigment. Artificial forms include orange swordtails, Xiphophorus var, and Orange Laser Corydoras (Aeneus). Naturally occuring ones are the Red Devil, Amphilophus Labiatus.

Sometimes any of the above can be seen in tandem, or in partial coverage, creating marbled or blotched patterns, the most common Amphilophus species above and a number of Malawi Cichlids.

I hope this helps people to realise the different colour strains available in the different fish species.

 

[Dwarfs]

=That's some good stuff to know

 

[Loupe]

Yeah, that is interesting.

 

[Aquamick]

Just thought it might help some people.

 

[Fish Buddy]

Thanks!!

 

[Aquamick]

You're welcome

EDIT add smiley

 

[Tempestuousfury]

Add a bit about scales and mouths and you have a wonderful pinned thread.

And what about guanin and the "silveriness" of fish?

 

[Aquamick]

Good point, Tempestuousfury *Goes off to check source-will return shortly*

 

[Aquamick]

Genetic Deformities Of The Skeleton

Some common deformities;

<Deformities of the head, particularly the jaws, creating a twisted or foreshortened appearance. This is not very common.

<Deformities of the spine: scoliosis (visible from above, lateral) and lordosis (visible from the side, verticle). The above can appear in tandem in certain individuals. The deformation of the spine can put pressure on some internal organs, sadly often requiring euthanasia. Twisting of the caudal peduncle is usually genetic in origin.

<Deformities of the Operculum, which may be wholly or partly missing. Common in in-bred fish. This seems to cause no distress to the fish in question.

<Deformities of the fins. Fins may be wholly or partly missing. Often only the odd membrane or ray is missing, but in the case of the pectorals the entire fin may be absent.

<Siamese twins are occasionally seen in livebearer fry, but very rarely. Euthanasia is practically obligatory.


Skin Deformities

The colouration of tropical fish is mainly due to chromatophores (pigment cells) within the dermis of the skin. Several types exist, the most well known being melanophores, xanthophores and erythrophores (see first post, the over-production of these pigments causes Albinoism, Melanism etc).

In addition to the chromatophores, the skin contains cells called iridocytes. These function to reflect light, giving the underside of fish a silvery appearance. Iridocytes are composed of a reflective material called guanin.

Hope this helps a bit more. Thanks, Tempestuousfury, for giving me the idea.

 

[Fish Buddy]

Some of my Rosey Barbs have a bumb at the base of the tail with the tail slightly folded. Would this be a spine deformation?

 

[Tempestuousfury]

Are you going for just mutations and deformations, or evolution and adaptations as well?

 

[Ahmad]

WOW great info!!!!

thanx alot!

 

[Aquamick]

I thought I would just concentrate on mutations and deformations, evolution and adaptation is a really big topic. Who knows? Sometime in the future I might post another section on evolution. It's something I'm becoming interested in.

Not sure Fish Buddy, it could just be a tumour. These aren't usually a problem to the fish, but I'm by no means an expert.

You're very welcome, Ahmad.

 

[Aquamick]

I'm going to look at some more places, and do some more research. It might take a while, though!

 

[Fish Buddy]

What do you mean 'evolution'? The fish aren't changing before out eyes are they?