Hello Martin,
the older fry only could have been found microorganisms that have been in the tank, because I didn’t feed any special food. But the tank is sort of crowdes, with a lot of leaves on the ground. Maybe an excellent place to hide and find the first food.
3 times a week the Fishes get Artemia nauplies. Sometimes I actually offer some portions of “rettichtierchen” (Spirostomum cf. ambiguum), microorganisms that look a bit like paramecia, but it is much easier to produce.
The parents mostly ignore the rettichtierchen, but the fry love it.
Meanwhile i can see about 10 – 12 young fishes at different ages in my tank, and they parenta are about to breed.