cichlids, please - PLEASE help

Question
I have a 10 gal tank. started with 12 fish, 10 cichlids, and 2 algae eaters - I
wasn't advised that the tank was way too small but eventually I was told an
additional filter would fix that at least until the fish got too large for the tank.
so  I have 2 filters running, the cartriges get filthy and have to be changed
perhaps bi weekly or triweekly... I came home to one dead fish last week,
today I came home to 4. I think there may be something on the fish' gills.
there is some kind of recent blow up of green or brown algae or something
on the walls of the tank and it spread to the greenery and rock inside. i
removed the rock and green today when I saw the fish and I did a 50 % water
change in case the chemicals inside were off.  the water is 78 deg F. I was
given info from petco stating that they like 72-82deg.  after I changed the
water I put in some water stabalizer stuff  and walked away for a minute. then
I noticed another fish swimming crazy in the tank bouncing off the walls, out
of the water. then a few others. from my original 12, I have 4 fish left. these
are my babies. my first pets and I'd like at least 1 to survive the night. I can
supply whatever info you might need. please help! thank you! my email is
mikewalt820@gmail.com

Answer
If the tank is holding so many fish you might have some crazy build up of ammonia that is way too many fish for a 10 gallon.

Ammonia will kill the fish fast. I would recommed quite a large water change. Use Cycle if you have to. (an additive to water to reduce fish loss during water changes)  Scrub the alage off the walls. Your water temperature shouldn't be a problem.