The puzzle changes each time you play, on my first play through it was a fish but on my second one it was a snake. The part at the end of this chapter can be quite annoying, especially when those fly type creatures spawn.
To get past the puzzle you have to go on the back side of the wall and hit a switch. That will move the horns on the ram's head on the other side. Then look through the wall. He painting on the over side will change to a snake. What you have to do is go around to each of the tablets around the room and change it to the back half of the snake. Then you can leave the room.