When is it time for a mercy killing? Have a lubbocks wrasse in qt with 3 others. 3 are doing fine. Wrasse now on side at bottom of tank. He rallied a bit for some food an hour ago but now on side again, sometimes belly up. He is in 2.25 ppm copper power for last 8 days. 100percent water change yesterday. Just don't know how long to let this go on.