You say "anemones." Do you have more than one?
3 months is a pretty "young" tank, for any anemone. A 3 month old tank may not even been completely cycled yet. Anemones prefer a established and mature tank. Most don't recommend any anemone in a tank less than 12 months old. That's 12 months AFTER the tank has completely cycled.
What type of anemones do you have?
This is important, in helping us diagnose your problem. Some species of anemone are naturally rock dwelling anemone, while other species are naturally sand dwelling anemone. Knowing the requirements of your species of anemone is very important in helping to make sure you're providing for it's needs.
How long have the anemones been in your tank?
What are your water parameters? These would be the most important, at this time.
Ammonia
Nitrates
pH
Salinity
Temperature
What other tank mates do you have?
In the future, any time you're having issues, and are requesting information, advice or help, it'd be very helpful for you to give us as much information as possible, about your tank. The more information we have, the better equipped we are, to help you.