Now before you allow yourself to get carried away with all kinds of ideas for how to set up an aquarium to be crazy fun, you have to understand that you can't just throw anything in there that looks colorful and cute. You see, fish are very small creatures. And that tank of yours is pretty small, too.
Just imagine what it would be like if someone shut you up in a 10 foot room with no windows or anything and just kept you there forever. Imagine next what it would be like if they put in your room, something that smelled awful – a large cheap plastic doll for instance. Pretty soon you, the cheap plastic would stink your room up. You might even get a headache from all the fumes.