Ah, o.k. that´s interesting. So I will leave the pair in the small tank.
For the offspring are fine, I will leave them also. The linkei seem to be well in their parents tank till now too.
Soon the new tank will be ready for them (the young linkei). So I will do for the phoenicurus too.
And when the spawning pair will stop to have offspring, I can put them in the bigger tank and try a new pair.
But I saw, that even in my small and not so “old” tank their was much mulm where I think the offspring got infusoria.
Also my linkei seem to grow quick. I had just the five who where behind the math filter in a breeding tank (the rucksack tank) and four of them survived and I put them again back into the parents tank.