Umm, I made a big pause in posting the photos. Unfortunately the hybrid fry had some troubles with health while my new year celebration:(, but now he looks OK. And because of that I made 7 days pause in taking daily photos.
The fry 42 days:
The fry 43 days:
The fry 44 days:
The fry 45 days:

Now it is already seen that there is a problem with caudal fin.
The fry 46 days:
The fry 47 days:
The fry 48 days:

Now looks really badly.
I suspected that the problem was some sort of aeromonos. (the fry was alone in the rearing tank, so the version that it could be beaten is wrong

)
It was quite strange because this disease happens due to bad water conditions. And I change water in this tank every day with 30% of total volume and clean my filters quite often. And to make the water better I made additional water changes and filter cleaning. But it didn't helped.
I suspected that the problem was in the algae that covered more than 50% of surface of the rearing tank. I always thought that algae is good. I took the fry away from the rearing tank and cleaned the rearing tank with the top water and sponge from algae. When the tank was absolutely clean I put it back, filled it with the water of the main tank and put the fry back. On the next day I noticed that the disease stopped progressing. And the fry started to eat well, before he had problems with eating. In few days I noticed that the fins were getting better and better.
The fry 56 days:
The fry 57 days:
The fry 58 days:
Now it seems he feels and eats good.
I added some Hypancistrus sp. L174 subadult to the same rearing tank.
The group photo (The hybrid fry 58 days):
