I saw this interesting freshwater crabs for sale in Kiev Pet Market. There was this really old guy selling them. He claims that they are fully aquatic and fully freshwater. He also claimed they he breeds them. But I am not sure if I could really trust him 100%. He could not really tell me much about the actual crabs and did not not the scientific name for them. He simply called them Holland Crabs)))
I looked around online and I think that these are Potamon potamonis olivi. It seems that they are most likely brackish. Not sure if they can live in freshwater all the time. But this guys claimed that they can. So who knows.
So if anyone knows anything about these freshwater crabs, please let me know. I am kind of curious myself.