Put a filter media in your sump, like marine pure spheres or any other bio media, in a month or so it should have a significant bacteria population, so you can transfer this media to a HOB filter in the 10 gal QT, instantly cycled tank.
Do you have any media in your 10 gallon right now? If so, it's probably cycled. Easy way to check is dose 2ppm ammonia and check after 24 hours. If there's any trace of ammonia, don't put a fish in. If there's not, you're good to go.
10 gallons should be fine for one.. I would do it. QT only though don't get me wrong haha..
Honestly, if you want success, listen to these people. I myself have never kept anthias, and probably never will because of the feedings they require and my schedule is very erratic and changes a lot. Everywhere I read says 3x a day, minimum. I wouldn't push that. Do 3x feeding a day or more, especially in QT. if you can't, skip the fish.
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