One time someone asked whether or not they could put a blue tang into a 20g tank. I instinctively said no, and told the person that the blue tang would not be happy in that tank for any amount of time, really. This person then responded with, "well, people shouldn't be keeping fish in tanks to begin with, so this isn't that bad" I didn't know what to say, or think -what would you have thought, or replied with?