hi everyone, id like to change my gravel to sand in my 20gal. tank. i have baby guppys(alot of them) 5 neons, 2 clown pleco, 1 clown loach, 3 redtail blue loachs, 2 cory cats and 1 oto cat. i also have a few plants that are not doing too good. should i take out all of my fish and plants or just...