Major Problem!

[Loopyness]

Not entirely sure whats going on in my tank , but all the water has gone cloudy, and fish are getting white stuff over them and dying within 24hrs of getting this. At first i thought it was an outbreak of fungus, so i treated it with interpet fungus and fin rot treatment, but this hasnt seemed to cure anything, i also did a 40% water change this morning, and found two more dead fish! The fish that are in the tank are gasping for air at the top of the water, but i cant see any white stuff on them at the moment. So far it has killed my red fin shark, two mollies and a catfish.
My tank has been running a long time so its mature and everything, everything was going okay until this happened! Any help would be really nice, thanks!

 

[WILDER]

Please post test results in ammonia,nitrite,nitrate,and ph, what size tank, what fish and which kind, maybe rinse one of your sponges in old tank water to make sure they are not really messed up, what filter to you use, if the patches are fuzzy on the body this is what you have.
http/www.flippersandfins.net/flexibacter.htm

 

[Loopyness]

that is exactly what my tank has got!!!!!
Cant test water until friday, because i am at work all the time the fish shop is open, and its miles away.... will do it then.....
Its a 124L tank and its got tetra's, danio's, two catfish, clown loach, gouramis in total about 25 fish. The filter is a fluval 2plus (i think).
I put the anti fungus and fin rot in on monday, when would i be able to put more in?
I have turned the temp down to 24c and moved my filter to the top to slightly improve oxygen.

 

[WILDER]

Do an immediate water change your filter isn't big enough for the clown loach, they need really big tanks, how big is the clown loach.
http/species.fishindex.com/species_2858b...lown_loach.html

 

[Loopyness]

just found out my filter is a 3plus.... sorry bout that!
Its about 2 inch at most, and will be getting a bigger tank in the future, so when they do get bigger there would be more room.
Have done a water change already!

 

[WILDER]

Keep an eye on water quality that will tell you if your filter is up to the job, and that you are maintaining the tank properly, good luck.