UK, Ireland / Registering a motorbike in Poland and shipping a fish tank there [5]

Ok, here is the question.
I leave in Ireland and I am planing to move to Poland, I have a big motorbike 1500cc, I would like to know how much would I need to pay to register there in Poland? Motorbike is Irish registration.

And other thing, I have a big fish tank, would I be able to bring my fish over?
I will rent a van to move all my stuff.