The pain that humans feel is the response of nerve endings of our skin to force, heat and chemical stimulation. Fish also have these nerve endings, but that doesn't mean they feel pain like us.

The signal transmitted by human nerve endings is transmitted to the higher center of the brain through a neural pathway, where we can identify this signal with what we call emotional experience of pain. Fish's brain is not so developed, and there is no corresponding part to perceive pain, so when nerve endings are touched, they will not perceive a feeling of pain, but will produce a reflection, and fish will not understand why there is such a reaction psychologically.

This clown fish is hidden under the protection of anemone tentacles, and the sea