What type of medicine would you use to treat ich in a mixed and/or nano aquarium? Can Melafix be used in a tank with anemones, starfish and coral? Are there "maintenance" medications you can use for typical stuff?
There are a few medications considered "reef safe" for ich, although they generally are not as effective as non-reef safe medications. Two examples of reef safe ich medications are Kordon's Herbal Ich Attack and Ruby Reef Kick Ich.
Although there are reef safe Melafix medications, there are also more effective medications for treating ich. Plus Melafix can cause excessive foaming, so if you're running a protein skimmer, it could generate some serious foam. Prazipro is not reef safe and may actually kill worms beneficial to your aquarium.
Some hobbyists have reported that reef safe medications are less effective. Some have even stated they are harmful to reef inhabitants, despite the "reef safe" label. So your best best is to treat fish illness in a separate quarantine (or "hospital") tank. Quarantine tanks (QT) can be relatively inexpensive to setup. They'll also save you time and money in the long run, allowing you to treat your fish with stronger medication and eliminating the inherent risk of using medicine that wasn't meant for the corals and inverts in your reef tank.
The MarineDepot.com Forum has a section dedicated to Disease, Health and Wellness, hosted by Kelly Jedlicki. Kelly pinned useful FAQ/topics at the top of the section chock full of great information on medications and treatment.
As far as "maintenance medicines," I wouldn't suggest preventive dosings of medications since you could create the reverse effect and allow diseases to build a tolerance to the medicine.
I recommend instead using food supplements like garlic or Selcon. Building up your fishes' immunity will go a long way in preventing disease outbreaks. In addition, maintaining optimal water quality in your aquarium will also help to reduce stressors within the tank.
If you would like to ask Keith a question, click here.