Well, I've been trying to decide between getting a cat or a fish tank. I've never actually had an indoor pet which is free to roam around, I mean I've had birds which I used to take out of the cages and play with but its not the same if you know what I mean. So I'm definitely leaning towards the cat but there's a lot of things going against it, firstly, my dad(not too fond of cat hair and cat smells) My unconfirmed allergy to cat hair, the financial investment and the further expenses. Because I want to get the expensive Persian breed.
The fish tank is actually easier to get and keep but I'm pretty sure I'll get bored of it in a day.
If I had the space my first choice would be a dog though.