help!!!

[myfriendpeter]

a week or so ago i had a fish who seemed narcoleptic, he'd all of the sudden lost conciousness and tumble to the bottom, then regain conciousnous and swim away.
he then died and i sadly went on.
suddenly now i have another one of my larger green barbs whos been stricken with the same thing!
he stays away from the other fish, hanging out by himself, and suddenly sometimes tumbles to the bottom like hes dead
the other fish again appear un affected and im really worried that whatevers happened(ing) to these two fish will slowly knock off the rest!
im doing regular water changes of 20% of the water, everything is seemingly normal i just have no idea whats happening to my fishies!
help???

 

[cometcattle]

Did you get your water tested? If so, what were the results?

Has your tank been properly cycled?

 

[myfriendpeter]

yeah its well established, i think it may be a water quality problem, as i just checked the filter and its pretty gross, im changing the medium asap!!

 

[The-Wolf]

yeah its well established, i think it may be a water quality problem, as i just checked the filter and its pretty gross, im changing the medium asap!!

If you change the filer medium you will make you tank re-cycle as
you are getting rid of the benificial baterium the is in there.