Quarantine prior to display placement is always ideal to isolate pests and disease in a system set up for treatment as apposed to a system that cannot be treated without negatively impacting health of inverts and other livestock. Not all fish can be treated with copper for example as some are sensitive to it.
When treating ich it is first important to understand the lifecycle of this parasite.
Stage 1. Trophont:
This is the stage where you see classic symptoms: white spots (like salt grains) on the fish's skin and gills. The parasite digs under the fish's skin to feed on it. During this
Everyone will need a lot more information to begin reaching a conclusion as to why it happened. Once we understand why we can help find the solution to it.
Water parameters, lights, light settings, age of system, bioload etc all play a part and will help everyone help you with better advice tailored to your particular situation.
Making me feel good about passing on Aperture. You are so deep into Apex swapping would be a nightmare though 😬. Hopefully CoralVue products give me a smoother experience. So far Hydros feels pretty solid. We will see how it goes as I get the collective running.