I'm not sure, but from the size of it's parents, it isn't a dwarf species. I would also recommend that you, if you have not yet done so, check the water chemistry (particularly for nitrates, ammonia, and metals).
In your pictures, I can't see the 'white fuzz'. Do you mean the pleopods beneath the tail (swimmerets)? Some crayfish, and shrimp, do grow what looks like fur, as they mature. This is usually located on their large claws.
Test results came back as:
PH--------8.4
Ammonia-0
Nitrite----0
Nitrate---20
Do you think that my ph is too much for it?
The white stuff is on the back and top of the tail and isn't visible really in the picture. It's almost translucent and the only reason i saw them was because the current in the aquarium made them sway a bit. I actually am thinking that they are growing there because the crayfish doesn't move anymore, it just sits in the corner or underneath a plant and doesn't move...