Final Fantasy 5 Ronka ruins Bluemagics (You will want those) 

This Hydra is pretty damn tough enemy without blowfish and level 16. I count my EXP bit wrong and i was lazy collect 4 more levels.

Thats how i did my four job fiesta playthrough. I´ll really recoomend you are level 20 when learn L4 Graviga or everybody know blowfish before, then its could be done lv 16 much easier than done here.