Fish Dying After Adding New Fluval 3

[lisajane1969]

just hasd a phone call from my friend, her mom has put a new fluval 3 in her tank, size 36 x 20 x 12, says her ph is 7.5, but her fish are dying, anyone help please?, i suggested water changes & strees zyme to build the new filter up.

 

[mancin]

Was the media from the old filter transferred over to the new one, or was it cleaned in tap water by any chance? From the sounds of it, the bacteria may have been wiped out or not transferred over at all if she's using brand new media.

Have her check the tank stats: Ammonia, NitrIte, and NitrAte and bring those numbers back. Water changes will certainly help (and multiple may be necessary) if there is an excess of Ammonia or NitrIte. My guess is if she just got the new filter, there is an Ammonia spike.