Is it normal i think the mouth leech is a fascinating creature?

This is a type of leech that attaches to the tongues of fish. What they do is eat the fishes tongue, replace the tongue and start draining the fish of its blood. These creatures do not do anything to people. So we are not in danger. However when researchers found this out they believed we should stop fishing. I myself generally do not eat fish. I just enjoy studying parasites.