Fish acting very strange and an algae problem

Question
I have a sunburst platy, dalmation molly, and a black molly.  For quite some time now I have had a green algae bloom that won't go away.  I've reduced light, reduced feeding, and tried algaefix but nothing works.  Very recently, though, the water was really green that I could not even see all the way through it.  I have taken my water up to petsmart and they have tested it for everything and it is all good, just green.  But now, for a few days, my fish are acting strange.  My platy won't eat, it just floats at the bottom and usually only moves if I wave my hand in front of it.  My black molly a couple of days ago would just float around the tank upside down and turning over.  My dalmation molly now keeps floating on its side and upside down but i see its gills moving.  Ive taken the net, when i thought he was dead and lifted him out, and he wouldnt flop or anything.  But then I put him back in the water and after a few seconds he would flop around and go crazy.  All three of my fish seem to not swim at all anymore but then dart REALLY fast if i walk up to the tank.  And none of them will eat.  Please help me, I don't want to lose them!  P.S. A few days ago, when I got my water tested, I also bought a pleco to help with the algae and it seems to be doing fine so far.  Also, I did a major water change yesterday so its much clearer but still cloudy and a little green.  Please help me!  Thank you. P.P.S. It's a 20 gallon tank with regular filter and a bubbler.  Cleaning about once a week with syphon, I syphon out the gravel so I don't think that's the problem.

Answer
Hi Danielle,
Green water is caused by two primary algae triggers - excess light and excess nutrients.

An algae bloom means your aquarium is not balanced.

The keys to getting rid of such a problem is to not use chemicals (which can be harmful) and instead target the cause of the algae bloom.

Start by doing -daily- 50% water changes. This is work I know but it is vital for getting rid of the nutrients fueling the algae bloom.

Limit light by keeping the tank light off most of the time except when you are viewing the fish or feeding them.

If you maintain this routine, the algae bloom will be deprived of what it needs to flourish and will go away. Just don't give up.

For your fish, they might be suffering from some kind of water quality problem. Hopefully its not too late, but the best thing to do is water changes. Always make sure the new water is treated with water conditioner and the temperature is equal to or just a bit warmer than your aquarium's.

Best of luck and I hope this helps!
Karen~