get as much mechanical filtration on the tank as possible, also, a couple big water changes (like 75% if possible will take a lot of the stuff out of the tank. It is usually reccomended to take out your fish before you do something like this but I believe they will be okay.
i can't think of anything that will hurt the fish beside the beneficial bacteria might die so keep your eye on water chemistry. also some harmful germs might come out also. again those are just what might happen. so don't be too worry but prepare for anything
Run your net through the water to remove the larger debris, as well. I wouldn't worry about it much, though. My 55 looks like that every time I do a major pruning and/or replanting. It should clear up very quickly with good filtration.
You have just unleashed the UGF TimeBomb! Oh that stored fermenting crud!
As mentioned above crank up the filtration, and the net scooping is a good idea too! I think the fish will be ok...
Find the nearest concrete wall, and bash the UGF to bits - throw it hard - serveral times (eye protection is probably wise so you also don't get crud in your eyes..) Now, find the nearest trash can for that ancient, old fashioned "filter"... HTH
Feel any better?
Your fish will, since if you followed these directions they will never have this happen to them again....
Oh my God am I in for a lot of work!!! I did the water change while waiting for replies here. I netted all the big **** out, but theis a ton off tiny stuff that the net won't catch. Hopefully the filters will get the rest of it... Unfortunately, one of my other filters broke down a few days ago, so i could be in for some problems. How much will a new good quality filter cost me?