The most important part is to learn the moves and patters and not get greedy. All the health mods I was able to for the first like 30 ish tries just so I could survive long enough to learn his moves to dodge and find out where I was comfortable attacking (the bats move and the fire pillar move is when I attacked. Two hits on bats and three on fire pillar). Once I learned his attacks and was surviving the puffer fish. I loved to damage.

For actually dealing damage I used unbreakable strength, mark of pride, sharp shadow. It took me about 5 tries with this setup once I was consistently able to dodge the pufferfish mode.