Wow. Starting from scratch?
There is a lot of information through books that you may need to know starting off the bat. Abebooks.com has several good books on breeding clownfish and I suggest reading multiple sources.
Clownfish broodstock can typically be kept in ten to 15g standard aquariums. Each pair belongs in their own tank. A breeding operation should have multiple different species of clowns and possibly other fish.
Each species of clown have their own cycles and how long it takes for the eggs to hatch. There are multiple different types of medications that need to be kept on hand for the inevitable disease.
After the clown eggs are almost ready to hatch, they are put in their own egg hatching tanks which are round, black plastic and have standpipes in the centers to drain water. This step requires live phytoplankton, Rotifera and enriched Rotifera and eventually enriched brine shrimp and mysis.
As they outgrow the hatchling tanks, you move them again to grow out tanks. Grow out tanks are usually large enough to hold each batch of fish and each tank has its own Seperate filtration just in case there is a disease. Grow out tanks need lots and lots of filtration because you will be feeding a lot of food and a few will be dying. Lots of ammonia- so a large trickle filter and/or decent sized fluidized sandbed filter will keep the ammonia levels almost nonexistent.
Some things to note: large skimmers, pumps, some lighting , food, tanks, saltwater mixing vats, a large RO unit, large phytoplankton growing systems, rotifer and brine hatching and growing systems,.... They all add up to a lot of money. Your talking a lot. At least on a small scale commercial operation. Now, home breeding might not be so bad, breeding one or two species at a time and getting a hang of it. Just remember that at any step or stage, things can go sour. Something might not be fed on time, ammonia problem, a phytoplankton batch crashes, etc.
Now talking about wholesale fish and the money behind it,... A single pair of clownfish breeds every 28 days I believe. It takes 9-11 days for a batch to hatch. A batch can be anywhere from 80-120 or more, depending on species. Maroon clownfish have batches of 1200+! And with time if you get good, you can have a survival rate of 80-90% and a cull rate of 5%~7%.
A clownfish sold at wholesale will be about $5-6 each at least that was the going rate in 2009. It might be closer to $6-7 now. Now here is the problem: imagine you have four pairs of broodtock clownfish and you have an average of 100 live per batch to maturity. That's 400 fish every 28 days. Eventually those fish that you grow out need to be sold - and at 400 fish per month at $5 each your only looking at about 2k per month minus electricity, possible rent, filters, medication, food, water, and so on.
Ok, the problem is finding enough buyers every month to make that quota. Most online retailers already have vendors that they trust or have contracts with like ORA. If you decide to sell them retail online, at 400 a month every month, you may be eating your fish instead of selling them.
Imagine having two to three pairs of maroon clownfish breeding 3000 good fish every month. It's not an extremely popular fish, but they hatch a lot of eggs- you'd be stuck with a lot of them jnless you can find buyers.
Not saying that it can't be done - it has been done before. Just saying that there is a lot to consider.
What I may suggest is breeding specialty clowns that are not copyrited as well as other popular demersal or mouth brooding fish that aren't as common as clowns.
