Olive Oyl accidentally knocks her pet goldfish overboard from Popeye’s ship and fears that the fish will drown, so Popeye goes to elaborate lengths to save him.
All righty then, let’s examine this one point by plot-point. Olive’s fish is in water to start with, but when the fish ends up in the ocean, Olive thinks he’ll drown?? Then there’s the fish itself, who starts out acting as though he’s hyper-eager to be rescued and then spends the rest of the cartoon laughing at Popeye’s efforts to rescue him. Time for a fish fry, I say!
Some lovely animation (particularly Popeye stuck inside a sea creature) makes up for the obvious story defects.