a cold fish
Someone who shows no emotion and comes across as unfriendly or disinterested. The manager decided not to hire Bill as the store greeter because he came across like a cold fish during the interview.
a cold fish
If you call someone a cold fish, you mean that they do not show their emotions and can seem unfriendly or unsympathetic. Since the President is generally seen as a cold fish, it is all the more impressive when he does show his feelings. He didn't really show much emotion — he's a bit of a cold fish.
a ˌcold ˈfish(disapproving) a person who shows little or no emotion, or is unfriendly, reserved, etc: When I first met him, he seemed rather a cold fish, but actually he’s quite passionate.
cold fish, a
A person who is unfeeling, or at least shows no emotion. “Cooler than a fish on a cake of ice,” P. G. Wodehouse put it (Money in the Bank, 1942). He was scarcely the first. Shakespeare wrote, “It was thought she was a woman and was turned into a cold fish” (Autolycus telling of a ballad against the hard hearts of maids, The Winter’s Tale, 4.4). See also cold heart.
See also: cold