Answer:
This is an example of classical conditioning.
Explanation:
Classical conditioning is the process by which a live being learns and acquires a certain behavior by association to stimulus.
The unconditioned stimulus pairs with a neutral stimulus and this becomes a conditioned stimulus which triggers a conditioned response, previously unconditioned.
In this case, John has been feeding his fish and now they associate John arriving to them receiving their food, the stimulus. They have learnt to swim to the top of the tank by associating which is an example of classical conditioning.
