View Full Version : Duckweed and bacterial surface film

02-18-2011, 04:52 PM
Hi Everyone,

Recently I have started an open-top freshwater aquarium for the purpose of providing my minnows with a fresh crop of overhead duckweed for water denitrifying as well as snacking. It's a 40 gal long tank, and I have started the duckweed crop in a large feeding ring floating on the top. I have two 20gal Whisper filters hanging on the back, and will soon partition off their flow into the tank using styrofoam half-circles, since duckweed likes quiet water, and get rid of the ring.

My problem is this: a bacterial film has grown around the duckweed. It looks a little gelatinous with little bubbles in it, and it's holding the duckweed in place. It's also only in the ring - the rest of the surface water is clean.

Will this go away on its own in time, or is there sometime I have to do about it? Is this a common occurance with anyone else out there growing duckweed in their tanks?


02-23-2011, 04:23 AM
I was about ready to post that I had never seen anything like this and the next day I had it! Its not right around the duckweed, rather the whole surface has it. If I stir it up it just stays all bubbly and looks weird.