I have had a lot of luck with the anemones that I have kept. So, I am by no means an expert, but I feel justified in giving advice.
Though I would never "recommend" anyone to buy an anemone while their tank is as new as yours, you did mention everything was moved from a more established system.
The biggest reason for a "mature" system being needed for anemones is so that you don't have fluctuations in water quality. I have found anemones to be very tolerant in changes of salinity and temperature, but not nitrates. In fact, anemones are a great measuring stick for nitrates. Once you know your anemone is healthy and that you are feeding him what he likes and giving him plenty of light, if you ever see it slumping, a good water change will usually do the trick.
So, I would say that you'll probably be fine. Being that your lr is established and covered in good bacteria, your parameters should remain stable.
However, I hope you have researched lighting and have the resources to upgrade. I would NOT recommend keeping even a BTA under compact lighting. I have done it, but it's kind of like feeding a mandarin brine shrimp. The good thing is he's getting some nutrition, but the bad thing is it's the wrong kind. By feeding an anemone well you can maximize the energy it obtains through photosynthesis. But, like a mandarin, without the proper diet it is just starving very very very slowly.
Here is some great info on anemones. I hope this link is kosher with the mods. I apologize if it isn't.
http://www.carlosreef.com/AnemoneFAQ.pdf
Most anemones prefer strong current and lighting. Usually hiding indicates that it is being damaged in some way. They will recede into the rockwork to avoid being stung, picked at, or whatever is threatening their health.
Moving around a lot usually indicates that it is not getting enough flow. Try to point a powerhead so that it is sending a current across the top of your rockwork. This is the best method for enticing an anemone to a high point where it will get lots of light.
Climbing the glass is almost always an indicator that your light is inadequate. Until you can upgrade your light, I would recommend feeding every three or four days. I didn't see if you specified the anemone type. I've found that my magnificent anemone prefers angelfish preparations, and my rose bubble tip anemone prefers raw table shrimp that I buy from the Wal-Mart seafood section.
Good luck! Anemones are my favorite part of reefkeeping!
To celebrate our tanks success (cycled yes) we bought a marroon with yellow stripe clown and a green anemone to be his friend. Well, after lights out the anemone got the idea to check out the tank. He wondered around and is now hiding in a cave made by the LR setup. What can I do to convince him to move back out where I can see him. He seemed very happy yesterday. He was out and wiggling and got very excited when the clown fish would come near.
