There is probably not that much you can do in the first instance, apart from choosing the right fish. Early success seems to be very much dependent on the fish itself with the three main factors being; was it healthy to start with, will it decide to eat and will it be intimidated into not eating and generally giving up on living, by it's tank mates?
If you successfully get past these issues then diet may well be the critical factor at keeping it long term. An inadequate quality (note not talking about quantity) diet may gradually weaken the fish and make it more susceptible to disease and parasites.
My first regal attempt, over 6 years ago, lasted about 4 days. It was never given a chance by itââ"šÂ¬Ã¢"žÂ¢s tank mates. My current Regal has been very successful BUT my importer, who I have known for a long time and trust totally, thought it was the healthiest and most active regal he had ever seen (in the business over 20 years) and had selected it personally when he saw it in a holding tank in Singapore.
I donââ"šÂ¬Ã¢"žÂ¢t think it is a freak, I just think that it is as good as they get and I was very lucky to ask the right question, during the right phone call, at the right time. Even though it has got over the first hurdles well, I am still very concerned to give it an excellent diet and have put more effort into getting and making the right food for it than ever before.
Steve