When I was a child, I saw (and caught) crayfish in a small pond near a children's recreation camp. We made "rakolovki" - this is a grid stretched on a round frame, in the center of which laid a piece of meat that has already started to deteriorate. You throw the "rakolovka" to the depth, you wait 15-20 minutes, until the crayfish gather on the feast, and raise the "rakolovka" from the water. But we saw those crayfish only in the air, but how do they behave in the usual habitat?
I found out the answer - I saw it - when this summer I dived in a flooded quarry. There I saw them with my own eyes at the very bottom. It was quite difficult to see them — they merge with the background. Well, except that the red eyes that are a little different in color.
They slowly went about their business affairs, and some just sat in ambush under various snags. Crayfish actively started to hide when saw the light of flashlights near, but from us they would not leave! And now I know where and how delicious crayfish live :)