Anemones by nature have some strange habits, although there conditions are often reflective of the quality of the water from which they live. You must remember that Anemones totally deflate and open thier mouths to dispell any waste. Often times you will see your anemone totally deflated with a string of mucus like waste coming from its mouth. To the unknowing hobbyist it appears as though the anemone is on its last leg, although that is normal. Although it is not really good for anemones to inflate and deflate on a regular basis. BTA and RBTA anemones are known to be travelors and the more you feed the more often you will see your anemone laying delfated expelling waste.
Basically the symptoms you guys are all describing are rather normal. Any terrible odor or odd marks, cuts, or openings on the anemone are sure fire signs that it is in trouble. Make sure you have plenty of light 5-10 watts per gallon and are keeping your calcium, strot, and alk
levels normal and test for phosphates. Even more important for BTA anemoness is the use of Iodine. They absorb this and it helps them recoup from over illumination or any other damage.
Anemones are typically hit or miss. I bought a gorgeous BTA some time ago that did wonderful for several months then suddenly got a large abrasive cut that spead all over it killing it before the week was out. I personally dont like BTA anemones because they are such travelors requiring that all filter intakes be covered and they can sting other anemones and corals, making them tough keepers.