rams with an extra black marking?

[henry]

As some of the larger rams are being removed from the fry tank, and their siblings are starting to colour up and show their dominance I have noticed a male and a female that have what I think is an extra black blotch located on their left aft gill area. Of the whole batch I have only noticed it on one male and one female. The male's is not as pronounced as the female's and he only has it on the left had side. The spot on her right side is not as dark.  Mutant's I guess?  
Anyone had anything similar to this?

Pics attached
Richard

[mseguin]

Blue rams (and some other south american dwarves) tend to show quite a bit of variation in pigmenting, ranging from very aple to no black marks to speciemnts like urs, with lots of black marking. Markings on the opercualr covering are quite common, and often have an iridescence to them. I would postulate that they are probably strongly involved in sexual selection and exhibition.

[henry]

Thanks mseguin
They do look really different in comparison to all the others. This is the only batch of rams I have ever raised. In your experience, would breeding them bring out that traitin the young?
thanks Richard

[mseguin]

It's very possible, but I would avoid trying to isolate unless oyu really think it would make them look better. IMO, not worth the risk of inbreeding. I.e. the potential payoff of having more black isnt worth having potentailly very weak or disease-prone rams. Not saying u shouldn't breed together those two, just dont do it for multiple generations.

[henry]

The parents I orginally got were most certainly siblings. I really didn't want to breed another pair without introducing new fish. I do like that trait though, but I will take your advise and shy away from that.
thanks Richard