About the second set of pictures:
I still don't have a positive identification, it's probably a
Macrobrachium species, I guess.. but I have a few new infomations:
They are quite darker now, with a black and a yellow transversal stripe on the dorsal area. They are about 5 cm, in hard water, with a pH around 8, and one of them is carrying many tiny eggs...
Am I right if I assume that this means they will not grow much more and that they are happy with the water characteristics?
Does this help with their identification?
Thank you

Cheers