With I believe that tank raised are more comfortable in our tanks which makes them slightly less likely to live in an anemone that is not their specific natural wild host. They usually do come around, but it could take weeks or months. Wild caught are by no means a guarantee in an anemone that is not their natural wild host, but they have been chased and threatened with being eaten if they leave an anemone most of their lives, so they generally try to get their butts into something anemoneish. I strongly recommend tank raised for the other reasons mentioned below.
Since we're talking about ocellarous or percs in a BTA (that's the only anemone I would attempt in a 12g) you have things going for you and against you. BTAs are an anemone that they are less likely to dive right into, but getting a very healthy one helps a lot. The good thing is that in a small tank like that they don't have much choice about where they hang out and they will likely discover the anemone pretty quickly.
As for the size of the tank, in my opinion, the jury is still out. I am trying BTAs in an 8 gal which is much smaller than recommended. So far so good, but long term success is still a long way off. If you have a regular display tank to work with and use for frequent large water changes, your big concern will be lighting and temperature.
I'm not will versed in minimum lighting for BTAs nor what is in the nano deluxe, but the BTA in my oceanic biocube is staying dark and looking good. it sometimes extends to cover the whole top inch of water in the tank though.
Water temperature is a tough one. I'm still working on keeping it stable enough for me to be happy keeping anemones in here.
Hope that helps
(WC perc and locally TR O. clowns in a BTA in my 8g)
