3 Fish Lost In A Week...how Come..?

[tameem]

In the last week or so, I have lost 3 fish. Today I found a red swordtail dead. And within the last week, a black molly, and another swordtail. We had the swordtails for about 2 months or so. The molly was a fairly new addition, maybe two weeks new.
I checked my water testing,and no ammonia or nitires. We havent had issues with other fish in the tank as they are original inhabitants of the tank.
We did add a bushy nose catfish, and in one case it was eating the dead fish, swordtail. We are eager to return the catfish, as it produes alot of waste.

Any ideas?

Concerned fishkeeper.

 

[kribensis12]

Hmmm. What are your NitrAtes like? I would think that either this is the killer, or some bacterial infection. Did the fish show any signs of being sick? Also, this should be posted in the Emergency section =]

 

[rocknurworld2006]

Hmmm. What are your NitrAtes like? I would think that either this is the killer, or some bacterial infection. Did the fish show any signs of being sick? Also, this should be posted in the Emergency section =]

what is your ph and nitrate as said could be the problem?

Hmmm. What are your NitrAtes like? I would think that either this is the killer, or some bacterial infection. Did the fish show any signs of being sick? Also, this should be posted in the Emergency section =]

what is your ph and nitrate as said could be the problem?

also did u quarintine your bristlenose before adding it to your tank?