first off, know that it will probably die ... and 2nd, that if it somehow doesnt die, you will need a very large tank, and eventually a very large pond. (or i will buy it

)
as for the tank, use sand bottom, or bare bottom.
cold water is a MUST! 72 or lower
surface agitation is the key, however you go about getting it is a personal preference ... i liked a large bubble wand or air stone, the fish seem to like the bubbles, and it will also break up the surface pretty good
and i will agree with the post above that said you want an open swimming area, and be careful with tubes and stuff hanging down, they WILL get stuck behind things! if you have filter tubes, take a dish sponge, boil it to rid it of chemicals, and then stick it between the tube and the glass. it will save you from finding a dead fish ...
if you have any quesions, please post, everyone will tell you not to do it, but if you will be able to keep them long term, they are great fish