I have been keeping marine fish for 40 years, and if I have learned anything in all that time, it is that if you do not quarantine you will be known as a "former marine fish keeper" who gave it up because of a dreadful outbreak of something in their tank. It is only a matter of time. Quarantine everything! I routinely dip incoming corals in an iodine bath (had an outbreak of flatworms once), and hypo all incoming fish. Average survival in my DT is better than 5 years.