It would kill them. I have recently HAD to do it to prevent a tank with no electricity completely dying over an 8 day period (cold slows decay and can stave off a crash, as heat accelerates one), but every day another species would go into distress and die. This is not something you would want to do. I did have 2 species survive it, but no. Get a better skimmer, and keep up with weekly water changes if you have a waste/nitrate problem.