I'm pretty sure they are nocturnal. If they are black - they are boiruna. I'm not familiar with Black Pearl's stock, but most mussurana sold are not clelia spp. but boiruna.
I keep clelia rustica and the juveniles are in CB/V 70 tubs. Adults go into 48" or 66" Freedom Breeders. If given enough room, these are very active snakes. As the adults can get in excess of 6', I'm astounded anyone would stuff one into a 34" tub..................