Some can - for example, a pike is a predator, and it is a fish and so can swim
It is not exactly that they like to swim, they swim to get food and get away from their predators. It is one of their adaptations.
They swim away.
they swim away from their predators
So that they can escape predators.
they swim not run
So they don't get eaten by predators.
They swim fast and deep.
They swim sideways
Ink their predator then swim away
Weddell seals swim under the ice to protect themselves from predators. They live in remote habitats that also helps to protect them from predators.
Harp seals need to be able to swim fast so that they can escape predators as well as to catch fish to eat.
I would not reccomend trying to get your guinea pigs to swim. In the wild guinea pigs may swim for swim for a short amount of time but only in a dire emergency, such as a risk from being caught by predators or drowning