Animals are being put at risk because panic buying and supermarket purchase limits is making it difficult to feed them, a zoo owner has warned.
Chris Moiser, who runs Tropiquaria Zoo in Somerset, said his staff had been "scouring the shops for food".
He said if food becomes "unaffordable" many zoos will have to close and he will have to "consider euthanasia of some, if not all" of his zoo's animals.
Mr Moiser urged people to donate spare fruit and vegetables to local zoos.
He said some local supermarkets and shops "have been good" but some will not allow purchases of "more than three of any food item".
"This is fine, but we are not panic buying, we are trying to buy the normal quantity of food for our animals that we buy from that store every week," he said.
"A couple of hours shopping a week has become many times longer, exposing staff to a greater infection potential as they move from shop to shop, buying what they can."
Mr Moiser said the zoo's animals were "having to discover new foods" but feeding them was becoming more difficult.
"If many of us have to close we will, without financial support, have to consider euthanasia of some, if not all, of our stock as food resources become simply unaffordable," he said.
"This is something that we will hate doing, and that many of us will never get over."
He urged people to continue to visit zoos if they are able to.
"At the practical level, zoos remain a low-risk trip out," Mr Moiser said.
"They are mainly outside, with large, open areas, which means that you can keep your distance from other visitors whilst breathing in fresh air."