hi there gibbo, yes there filter feeders , i dont add any thing to the water
to harden it, the ph is 7, he's shelled ok so it must be fine for him, when
i do a water change he comes out from behind the filter thats were he's
made his home lol

and he goes mad filtering all the gunk thats
floating around, he's around 4inchs now think he's going to shed again cause he's gone really dark blue he's usualy light blue, he's a realy cool dood lol