They are nice pets, aren't they. When you consider upgrading his tank, keep in mind that they are great jumpers and a full grown one can fly out of the water in a flash. You will be better off getting a high tank, rather than a long one.
I've had to remove him from my finger before...He ALWAYS tries to gulp down my finger before the food,I had to pick him off of my hand one day he didn't wanna let go!