F0? F1? F2? Does it matter?

[ragin_cajun]

I know what F0 is, and F1. F1 is the fry of a wild caught pair. But what exactly is "F2"? Here' why I ask. If F2 is the fry of 2 F1's that are siblings, that is inbreeding. But if a breeder took an F1 from 1 pair of F0's, and an F1 from a completely different pair of F0's.....well those 2 F1's are completely unrelated. Their fry would be every bit as "genetically diverse" as any other fry produced in the wild and called "F0", right? so would those captive bred unrelated fish be F0? Assuming of course, all 4 F0's were of the same species and from teh same collection point?

And how much does this matter? I know fish are fine with alot more interbreeding than people, or dogs, or higher mammals. But at what point to problems crop up with interbreeding? And what happens? Colors fade and survival rates of fry decrease? Disease prone offspring?

 

[Beetlebug515]

I can say that I had some blue johanni cichlids that bred 4 generations between themselves and never saw any color reduction or diseases.

 

[duanes]

In my opinion, once you get beyond F1, whether a fish is F3 or F6, it becomes basically meaningless.
Genetic diversity in nature is effected not simply by unrelated individuals, but those tested by their environment, predators, by all facets of life and death. These unrelated individuals have run a gauntlet of tests no aquarium fish comes even remotely close to.
It is theorized that in nature, it is lucky if only 1 individual, of any spawn survives to adulthood, that is a major accomplishment.
These random "survival of the fittest" tests are why wild fish are so much different, and worth so much more to a concerned fish keeper, and why real F1s are so much more significant than the generations of untested aquarium crossed generations.