Ugla,
I have had one anemone killed that way from my percs, and had I not intervened with the purple H.magnifica, it would have happened to it as well.
Clowns do not often help a sick or weak anemone....keeping them away from a newly acquired anemone is generally best for the anemone, until you see it gaining in size and having a more rapid feeding response, (ie enveloping the food item, drawing it to its mouth, and then ingesting it. I find the ingesting part is what takes so long and is the most common time clowns will steal food from an anemone.
Stealing food from a weak/newly acquired anemone causes more harm because the anemone most likely doesnt have the energy reserves needed for long term survival. And it's expending energy by capturing the food, drawing it to its mouth, and attempting to ingest it. Low energy reserves, plus loss of energy by spending it in a failed attempt to eat = problems.
If your anemone is a species that is known to have long tentacles, and has short nubby tentacles, you can assume its either weakened, or recovering from a weakened state. Pale, faded coloration, short nubby tentacles in a species not known to have them, flacid gaping mouth...these are all signs of an unhealthy anemone.
Nick
