You use the phrase ‘Drink like a Fish’ when discussing someone’s tendency toward
consuming too much alcohol.
Example of use: “It’s not a good idea to drink like a fish, especially if you’ve got to be at work early in the morning.”
The origin of the expression ‘drink like a fish’ is a clear allusion to a fish’s method of breathing, namely to ingest water and pass it over the gills in order to obtain the necessary amount of oxygen. The phrase was first seen in print in 1640, in Fletcher and Shirley’s work The Night-Walker, Or The Little Thief: “Give me the bottle, I can drink like a Fish now, like an Elephant.”