Answer: Unconditioned response
Step-by-step explanation:
The stimuli in this case is light which leads to the response produced by the fishes. This is an example of the unconditioned response in which the body responses to the stimuli involuntarily.
This response is not a voluntary response this is a kind of involuntary response by the body.
This response is produced due to the stimuli which is given again and again. This response stops with time. Example: If the food is not given to the fishes even when when the light is turned on.
Then slowly the response of the fishes will go away.