Honestly, not sure about the depth. Id guess between 5 and 8 feet. Different sized rocks, probably from a mini basketball size to irregular soccer ball. I have not seen any crayfish evidence, and didn't filet any. I wonder if it's a food hangout, or just more of an attraction since it's different/irregular. The fish weren't big, but were big for my pond. Several 14 to 15 inch fish. Im trying to get them bigger.