OK, again, just my opinion...

The very first anemone I tried was in... gulp ... 1971. It was INSANE. A beautiful bright yellow anemone. You can guess how long it lived...

I've had anemones continuously living in my tanks since 2001. And I just about NEVER feed them directly. Yes, they manage to grab a bit of food as it comes by. In my 55, the RBTA which is about 11" across when fully inflated, hasn't gotten ANYTHING except pellet food that managed to make it's way into it, for at least 90 days. These critters are about 99% water - and don't need to be fed at the level folks typically feed them. They puke almost all of it up anyway. Feeding them heavily, IMHO, just puts additional stress on them. A light feeding - what they would get from casual feeding - is much easier on them.

Again, this is just my opinion. If I had taken that anemone as a rescue, that's what I would do with it. I certainly wouldn't do ANYTHING that might stress it out more. It needs a chance to recover - as slight at I think that chance might be. A light feeding of mysis or whatever would be the max I'd do - at the same time the rest of the tank was fed.

And, I could be completely wrong. Wouldn't be the first time.