After unlocking Z93(.50 sniper rifle) or SA50(.50 semi-automatic sniper rifle), every time you want to swim near the water surface, you must first stab an eagle eye medicine (marking enemies and animals), and you can hit the marked devil fish with one shot. Other weapons are either not powerful enough or wasted on shooting underwater fish. The most economical is two.50 sniper rifles (the modified version of Z93 in the signature weapon is also possible, except that one is.