The old saying that 'prevention is the best form of medicine' is very true of all marine disease, but especially true of Cryptocaryon. All new fish should be placed in a quarantine tank for at least ten days to make sure that they are eating, free of disease, and so they are not being bullied in a new tank. Any sick fish can be treated before being added to the display tank. Remember though, a quarantine tank needs to be clean; appropriately sized; have the necessary biological, mechanical, and chemical filters; and have adequate hiding places or it can actually increase the stress level of the fish.
Stress is the enemy of fish health. Cryptocaryon will target stressed fish with lowered immune systems. Anything we can do to reduce the stress that fish undergo will decrease both the disease incidence, mortality, and improve treatment results. Remember that almost all marine fish are wild harvested and are extremely stressed by the time they reach your home. These fish need to be handled very carefully to avoid disease outbreaks. They need to have perfect water quality, correct nutrition, a stable temperature, and places to hide and feel secure. If any of these needs are not met, then the already stressed fish will likely develop marine ich or another disease. h
Some owners will place all new fish into a quarantine tank that is being treated with copper. Remember that these newly arrived fish are very stressed, and copper or other treatments can add additional stress. Once the fish has had several days to a week to acclimate and is eating well, then prophylactic treatment can be performed, however, it is never good medicine to routinely treat healthy fish. In fact, treating healthy fish should be avoided in both the show tank and the quarantine tank.