With collections like Zetr0's, you might be in trouble anyway, but the rest of us should simply tell the lady of the house "it's either this, or a saltwater aquarium!"
Your going to run in to pricetags around 5 000 euro and climbing for a new 375-450L tub. And thats the very least you would start with, ofcourse. On top of that you will have a new electricity bill. Count on a tank of that size to consume 0.2-0.5kw/h, 24/7. (Thats after averaging out the lighting on the whole cycle)
One way or another, you CAN make the Amiga collection sound cheap.