Third time was a charm for me, actually, the second one I owned was doing fine until I added a new fish that came down with ick and took the clown with it.
First off, you need a large aquarium, as they tend to do better where they will have lots of swimming space since they are very active fish. They also need highly oxygenated water and don't do to well with PH swings. And if you get that taken care of, then you gotta hope you find one that eats as they are very finicky when first introduced. My first one never ate and eventually wasted away. It took two weeks to get my second one to eat, but after that, it was eating like a pig. Unfortunately, it contracted ick from another newly introduced fish. It was upsetting because I had a happy and healthy clown.
The third I got is still with me and doing great for nearly a year now. I knew this guy was a winner when I got him because it refused to die, very strong immune system. When I saw him at the wholesaler I go to, he was battleing ick and had wounds on him but was active and eating well. I asked why it was wounded and the guy at the wholesaler said he had dropped it when trying to move it to a different area. Because it looked bad, he told me I could have it for $5. SOLD! I took it home, treated the ick and and after a full recovery, put him in my main tank and it has been a fine addition since. To get them to start eating, I've had great success with live brine and then eventually frozen, in which I feed all my fish, only frozen foods. Be careful, as these fish are more of the aggressive of the tangs. Mine used to be timid, but now will not let any fish intimidate it. It doesn't bully any of the fish around, just those that try to bully him. I've heard of some becoming very aggressive though.
