It is in a 30 gallon biocube that's been established for a year. Salinity tests normal. Have protein skimmer and bio balls. Have lighting that I can switch from normal to blue. Only thing was the water tested a bit high on nitrates but got those levels back down to normal.
Ammonia was fine. Nitrates were high in unsafe levels. Put a balancer in to temporarily fix it but going to do a partial water change tomorrow.
First off, I'm not trying to beat up on you. However a lot of your posts convey little or no useful information. Consider the statements "Salinity tests normal. ", "Only thing was the water tested a bit high on nitrates but got those levels back down to normal.", "Ammonia was fine. Nitrates were high in unsafe levels. ", we know very little, because what might seem "normal" to you might indicate a major issue to someone else. Please post exact readings. It's the only way we can know what is going on.
Same thing with lighting. To evaluate if it's enough for an anemone we need to know the quantity, wattage, kind of bulb, and what type of bulb it is. for example a typical coralife biocube 30 had 1 36w Actinic power compact bulb and 1 36w power compact 10000K daylight bulb. However, it's quite possible the bulbs your using don't match these specs or that the lighting was upgraded.
I can tell you that if you have those original spec bulbs you don't have nearly enough light for an anemone. However, we can let this go for now, because it's a long term issue and not related to your immediate problem.
Anemones don't like high nitrate, and this is likely a major factor. However, with out exact readings, we can't be sure. Also, what was the "balancer" product you used? It's not likely this is an issue, but some additives can do a lot more harm than good.
On the picture of the anemone, this helps quite a bit. The mouth really looks bad. Keep a very close eye on this for any signs of decay. Also test ammonia, since an ammonia spike usually indicates something dead in the tank. Even so they anemone may not be lost yet. Sometimes they expel their insides, and even then sometimes recover. However a dead one will quickly foul the tank.
I think the chances of your anemone surviving are low, but you just never know. Sometimes you get lucky.