Железнопанцирный краб

There's deep water under a tree. I fished it from 2849,3336. There is both shallow and deep water accessible there. Bonus: there are 3 spots that artifacts spawn in the deep water under the tree

As of April 2020, this is still a good place to fish up Ironshell Crab and Inland Octopus. Look for the large tree. It is hollow in the middle and the deep water is there. There are a few openings to the center of the tree around the base. Fish from there into the center waters.