Hmmm..... well, location, location, location.
Also, market research.
You'll need to register a company name.
Find some funding. Venture Capitalists, angel investors, grants, etc.
Buy some land.
Build the facilities.
Get some marketing and advertising going.
Hire a few specialists.
Pay off investors.
Gain the rest of the revenue
Make sure you take care of your expenses of maintaining the fish and facilities, pay your employees, etc.
Just a basic business plan if anyone here wants to get serious about the idea. 'Cause I can tell you now, that's the basic outline of any business venture right there.
Good luck to whoever goes for it.