If this was just a poll my answer is above, do not read further and waste your time, otherwise...
Talking to ones self is an excellent way to work through issues and problem solve.
Interesting how quickly one can criticize a topic point which is greatly a subjective one, not taking into account so many variables.
Thank you Spock! Talking to fish is highly illogical.
Talking to ones self or to a pet or fish isn't crazy. There are clinical definitions people can look up and study if interested, but in this moment, I bet most every one here is not.
Verbal communication is simply one method of communicating. My fish don't talk verbally, if I thought so, that would be "crazy".
But communication is not only verbal. Animals, including fish communicate very well. And have intelligence. Learning to read clues/body language of people and animals could make you arguably more intelligent (stretching a new part of your brain,) and skilled.
Some are not as quick to criticize a "gamer", or Bill Gates or Thomas Edison, or Marie Curie for being obsessed. People have different passions, gifts and interests.
Aren't we glad there are so many choices of how we like to spend our time, who or what we like to spend it with and who we want to talk to, especially here in the USA.
Synopsis - Talking to fish (and inverts) is part of the fun!