Just wanted to clarify a few things:
1. Except for BTAs and occasionally magnifica, all other hosting anemones are usually "wild" and they can last a long time. Some of my gigantea are 5+ years old.
2. Zooxanthellae is almost always brown or green. The pink/green/purple/or orange colors as mentioned is usually part of the anemone (versus symbiotic, which zoox is to the anemone). This is why you can't change the color of an anemone by "feeding" it zoox from another anemone. Bleached anemone may look white, but the case color is always still present, just hard to see. When anemone regains zoox, the color comes back, but it's always the same color as it was before it lost the zoox. Color shifting occasionally occurs, but many times it's due to lighting (intensity or spectum).
3. These days many wild BTAs are A LOT more expensive than aquacultured BTAs, especially rainbows or reds (people are looking for the next CSB).
4. "Grasping" it not a key indicator of sickness. Many anemones die while still attached to a rock or substrate. On the other hand, BTAs in particular are known to detach and float around the tank not because they are sick, but because they aren't "happy" with lighting or water flow.