so this is like how you would determine the value of a pet based on the joy you get out of it compared to the effort you have to put in. tropical fish are a great example of a terrible pet because everyone you know who has had tropical fish at some point in their life has talked about how they will often just fling themselves skywards from the carefully temperature and pH-controlled climate you have diligently created for them, and onto the floor or just behind the tank, never to be seen again by either yourself or their compatriots as they waste out the rest of their days hopelessly flopping and leaving us all wondering why our hubris necessitated the removal of these stupid fish from their habitat in the sea