To drink like a fish is a common idiom which means to drink a lot and in excess.
That’s right, sometimes it’s great to have a civilised glass of wine but sometimes it’s heavenly to drink like a fish and crawl home on your hands and knees; or better still, stop a policeman and ask him to escort you home in his police car with the sirens going nee nor, nee nor, nee nor.
Inglés Málaga 