Ah, the exuberance of youth. I want to say, I sincerely wish you the best of luck in this endeavor. If you're truly serious and this passionate, then by all means pursue that with all the means you can muster. If it's sustainable, then I'll gladly be your first customer, no joke.
Maybe you'd be willing to take some advice, since it's been tried before.
- Learn the ropes by working at a successful aquaculture farm. There are quite a few out there, but most are geared toward the foodchain, not ornamentals. ORA might be a good start.
- Try building your farm in the ocean or with direct flow from the ocean. You'll save on chemicals, electricity and pumps. Carbon-neutral.
- Use natural sunlight. You can't get much greener than that.
- Build your artificial reef out of reclaimed concrete, limestone and volcanic pumice, score one for recycling.
- Give away at least 25% of everything you culture to reef reclamation projects... see, you're doing stuff for the greater good, too.
- Hire local labor. Most of the places this stuff comes from are impoverished and you'd be doing a lot of good for the community there.
- Once you get things going, chances are someone in a government will try and take it away. Bribe them early and often to not do that. It will cut into your profit margin.
- You will need a ton of luck and / or religion. Hurricanes / Typhoons / Earthquakes / El Nino can wipe out your entire investment in a day. Take a page from R. Lee Ermey in "Siege of Firebase Gloria"- there is no such thing as an atheist in a combat zone.
- You're going to need lots of seed capital. Make friends with rich people. Especially ones with more money than brains and an overdeveloped sense of environmental consience.
You may be able to kill two birds with one stone.. present your business plan to Richard Branson. He's got a private island, so no bribery needed for the above... just a lot of rent money. (You will have to name all your new cool color morphs as "Virgin" X, like the "Virgin Atlantic Super Whizbang Ultra Rainbow Acro", but totally worth it for two grand a frag.)
If you've stuck with me this far, look up Walt Smith Fiji International. Absolutely uplifting in how he succeeded in doing just what you want to do, but simultaneously the most tragically sad example of ignorance, government overreach and special interest money that destroyed his creation.
As an alternate career path, you may want to consider becoming a lawyer instead, fighting for those that are doing the right thing and helping to guide environmental regulations that are effective and based on proven, reproducible, non-biased science.