So I have an established 5 gal that is doing great. I've only ever done a 100% water change on it once and I'm wanting to do another so I can completely scrub the glass and clean all the gravel. I was thinking I could just scoop out about 2 or so gallons to put the fish in while cleaning, then clean everything (but not the filters since I read that that's where the bacteria is housed) and I'll add them back in with freshwater. It seems like it would be no different than how I usually do water changes, except the fish will be removed and the gravel will be cleaned instead of just vacuumed and technically it wouldn't even be a 100% water change. Should this work out okay? I'm mainly wanting to do this because my corys are occassionally rolling around the gravel and my Harlequin tetras appear to have a slight film to them and I figured it was some kind of fungus. So I assumed I would need to clean the tank good to help get rid of it while I treat them (I read that Paraguard by Seachem might be a good option) Any advice on either subject it greatly appreciated!