How much would it cost to set up a tank for two clownfish?

Clownfish are salt water fish, so I will put your question in the Marine fish section, you will find a lot of help there!

Well, you'll probably get a lot of opinions on this, but I'm here first so you get to start with mine. :-) It's kind of a harder question than it sounds like. First, two clownfish would need I would think a minimum of 20 gallons; they grow to between 3-4 inches. BUT--small SW tanks are really tricky and those who know recommend a minimim of anywhere from 30-55 gallons, with bigger being better. Nanocubes are notoriously hard to keep for newbies as even tiny changes in chemistery can crash the tank. (Which isn't to say it's impossible--ask Koko. It's just not usually recommended for beginners.) Estimates for getting a stable, reliable tank up and running are about $20-$30 a gallon. I'm setting up a 75 and so far, that's about right. I'll be well over $2000 into it by the time the fish are in in.

So--the answer is it depends. :-) I'd really encourage you to do some research before you decide:

"The New Marine Aqaurium" --Paletta
Conscientious Marine Aquarist by Robert Fenner

Both of these books are invaluable.

http://www.aquariumadvice.com/viewforum.php?f=7 (less active, more personal)
http://reefcentral.com/forums/forumdisplay...?s=&forumid=104 (zillions of posters)

Good luck! It's a fun hobby, but one that takes some research and thought.