My crayfish would always hide during the day but night was when he came out. If you drop some food in front of his hidey hole he will grab it and either eat it there or bring it back into the cave with him. Lots of hiding spots and fake plants will make him feel more secure, so he feels safe to come out during the day.
My tanks (so far
5.5 gallon Planted Dwarf Puffer tank (2 Dwarf Puffers and a lot of RCS!)
16 Gallon Planted
(GBR pair, 3 amano shrimp and a whole bunch of snails!)