Backyard Aquaponics
A place to discuss aquaponics

I am working on a selective breeding program crossing Rocky Mountain White (O.aureus X O.niloticus) with F1's O.mossombica. I'm consistently getting a 50:50 male female fry ratio. Male fry can be seperated from females at 2 weeks, that's what makes this hybrid nice. At first it was a haunch...I noticed significant difference in phenotype and began seprating the orange fry from the dark/grey phenotype. 3 months later my initial observations were validated by visual inspection of sex organs. Females were predominately orange with some black pigmentation. Where as the male population exhibited two different phenotypes. They are either dark grey with verticle stripes, or a very light shade of grey (almost white) with less predominant stripes. I must say it was a surprise to observe such an array of pigmentation, and this makes selective breeding all the more fun.
Don
http://www.tilapiahybridpair.com
tilapiahybridpair@yahoo.com

Very interesting

Sexing the fish is the hardest thing for me. So much so that I quit trying. I just remove larger fish to another tank and let the remainder grow out. I have no idea what breed(s) my fish are, but the fist offspring were orange, white, and black. I have selected the black out for breeding because of their better growth rate and good feeding rates at lower temps. What you said about the marking got me thinking about my fish. My females seem to be striped and the males seem to have a whiteish or orangeish face. Well. the ones I have noticed breeding and protecting fry.

Hello. Do you mind me asking what species you are working with? When I crossed a female O.mossombica with a O.horonum> My offspring had the following phenotypes: males were black with horizontal stripes, and thier black color became more pronounced when courting, the males also had a small red stripe that ran across the tip of the dorsal fin. Females were predominatly black with some orange pigmentation.
I'm selectivly breeding for the a completely orange female, and I get about 10% pure orange females when crossing my Rocky Moutain Whites with F1 O.mossombica.
Don
P.S. I have a really good website that has closeups of Tilapia sexual organs, the pictures were taken with a macro lens so its really easy to see the difference, as soon as I dig it up I will make sure to send you the link.
P.S.S.
Could you send some pictures of your fish and maybe I could help you identify the species you are working with. I have been involved with cichlids for 20 years.
tilapiahybridpair@yahoo.com

I have no idea what type of tilapia I have. They are a breakdown of some commercial
"brand". My females seem to have vertical stripes.

The problem down here is that the mossombica which are available to everyone can be just about anything. The commercial growers here generally consider it mossombica if its orange

I would be very interested of those Tilapia sexual organ pictures!

I will catch and photograph some of the smaller fish. Catching the large fish would be a lot of trouble right now without a proper net.
basically I have white, black, orange some times with black spots and now this last batch of offspring have the vertical stripes. Its almost as though the original orange fish were some type of mix to produce all male offspring, but obviously there was a female in the batch, and now they strains are separating. I have eliminated the orange fish because of their poor body shape and growth. I have only had 1 white off spring so far, but it exhibits the fast growth of the black fish.