In my opinion, any ammonia above ZERO is high. It is an indicator that you have not completely cycled your tank. If you test for NITRITES, I'd be willing to bet you find some level of that too.
I get the impression you are new to the hobby. So I am going to suggest that you SLOW DOWN and completely STOP adding anything to your tank until we get things under control.
There are some things we need to know:
- How many days has the tank been running?
- What are your Salinity, Alkalinity, pH, Ammonia, Nitrite and temperature numbers?
- What kind of lighting do you have installed?
- How big is your tank?
- Do you operate a sump or is it a hang-on-back filter?
- Do you run power heads to increase flow?
- What other equipment do you have supporting your tank?
- Provide a complete list of all inhabitants in your tank.
It is common for Anemones to shrink as lights ramp down and inflate as they ramp up. This wringing out and re-inflating is how they excrete waste.
Don't try feeding it yet. It sounds unhappy at the moment.
Remember: A reef aquarium isn't something that can be set up impulsively. You don't pull it out of a box, plug it in and enjoy. They need to be nurtured and cultivated. They are like a garden; they have to be allowed to grow with time and become the magnificent display you imagine it in your mind's eye.
Please provide a few FULL TANK pictures so we can see what you have.