What is the life expectancy of a Pink Tilapia? I now have one of my 3 1/2 year old fish playing possum on the bottom of the tank. She has been doing this for weeks...laying on her side not moving. As soon as I try to net her she swim away like nothing is wrong...old fish or sick fish?

Is she eatable or not? Leave her in the tank or end her life? Maybe the lack of oxygen from 2 months ago did some brain damage?

Hope to hear back from someone.

Thanks, Apollo