He hasn't actually gotten a fish yet, because, as he informs me:
Mr. Rose: I have to get gravel and fish food and you have to get it an "air stone" because fish will use up all the oxygen in the water and suffocate.
Me: Wait, that doesn't sound right... if they use up all the oxygen, does that mean they are just swimming in liquid hydrogen? Does it cease to be water? Since water is H2O and they're using ALL the oxygen...
Mr. Rose [interrupting]: Fine, let me rephrase that. I have to get an air stone because if I just put the fish in there it will die. I don't know why.
Me: I think it is because fish are assholes.