Inverts/corals just should be QT'd without fish. The most common marine fish parasites need fish to complete their life cycle, without fish the parasite dies off in roughly 5-8 weeks. For all corals QT'd you need to know what to look for ie: flatworms, red bugs, nudibranchs to name but a few.
You can dip most corals in any number of products such as RX or a Iodine dilutions. Anemones are a bit harder to treat prophylactically.
If you want to go the extra mile, the BTA and the Euphyllia can be QT'd together. The clown should be prophylatically treated for Cryptocaryans irritans in a seperate tank.
