This fish has a few names. Hippo - Regal - Pacific Blue Tang. They are very infamous ich magnets. They are captured from a region where cyanide is one of the collecting methods and they will not live long if they were caught with cyanide. If they were net caught, they have a good chance of survival, but it's best to keep these in a sick tank for about 3 or 4 weeks to see if ich shows up before you let ich overtake your main tank. If ich shows up, there are several medications available. The copper treatments are most harsh for the fish and I always prefer other medications or hyposalinity, which is a whole topic by itself. I never use copper treatments.
Tangs are not bred in captivity. The closest you may find is the ones that were captured as very small juveniles and raised in captivity. If you have hole in the head problems, it is often because of nutritional deficiency, poor water quality or possibly stray voltage in your tank. The most common problem I've seen with these fish besides the ich is that they squeeze into very tight hiding places and scrape their color off and it doesn't grow back.
If you decide to buy one or more, I think a 6 or 7 ft tank is a minumum size tank length because they grow quickly and reach around 10 inches or something in that size range. They like a lot of hiding places, some vegetation in their diet, although not as much as most other Tangs and meaty foods like Formula 1 and 2 and Mysis shrimp. Algae products should be a daily part of the diet and it would also be very helpful to soak their food in vitamin products at least a few times a week.