This is the part I didn't want to get to...here is the bad news, since you are unsere of your lighting then it is most likely not the lighting required for anemones.Proper lighting is rather expensive and you definately know it when you buy it. Your anemone will not survive in an environment without sufficient lighting. Supplemental foods will prolong the inevitable, but he will eventually starve and if you attempt to compensate by feeding more often you will put you water parameters in jeapordy thus another risk for the anemone.
Anemones are not easy pets, and we should not buy them siomply because they are pretty before doing the research necessary. Your best bet, sorry to say will be to return the anemone.
Or find out and post what your lighting is after you find out and maybe there is hope after all.
HOT*** I didn't mean to sound crude last night when I said don't go there, but I have been blasted on more than one occasion by "changing the topic" from the original question by asking about the environments parameters. Example following.
https://www.saltwaterfish.com/vb/show...highlight=tang
I was trying to keep you from being blasted that's all. But shels here, seems to be a more willing learner. :joy: