What’s about the gen-pool?
The question is justified, but the issue is overrated, too.
Since 2005, some breeders exchange individuals of secured identity (location!) at meetings. Even the exchange of of specimens of the same stock the have been grown at different places with different breeders add a certain amount of security. At the first international meeting that we shall organize at Hamburg 2015 there is a possibility to do this again. But identity not only of species but of its original location must be certain beforehand. Otherwise the procedure is likely to be contraproductive.
One could do this with commercially traded fish, too, although there is nearly never a given locality. But it is to be recommended with secure species determination only. That means, all Sumatranian bintan-variants should be excluded. For linkei or filamentosus or ornaticauda it could be worthwhile, not for bintan-types.
On the other hand the following is to be taken serious: The issue is overrated. What we do, is artificial breeding, i.e. we can, should and do exclude aberrant or ill young individuals from further breeding anyway. In this respect the issue is blown-up to a huge problem, but it exists in nature only if the real gen-pool has become very small. There is nobody who controls the reproduction; this is quite different in our case. Most cases of complaints about genetic defects in breeding fish are due to mistakes of the breeder. He is responsible; the issue of the “too small gen-pool” is mostly an excuse for a bad care and conditions not provided as optimal as possible.
See the following example which is really impressive: There was only once an import of P. quindecim. All quindecim we have all over the world refer to this import. There is one German breeder, Bernhard Lukiewski from Berlin, who since the breeds quindecim in high numbers in the twentieth or so generation. He does it with excellent care, feeding and knowledge. He never observed any signs of degeneration in his fish. The point is important for natural stocks, but highly overrated for aquaristic ones. Nearly all amounts to the skills and consciousness of us, the breeders.