new filter killed all my fish

[Martin]

I have (had  ) a small goldfish tank with a couple of small fish and some WCMs. I had one of the old air powered filters which worked OK for 10 years but recently it started making blob-blob noises rather than releasing a stream if bubbles, that was about 6 months ago

I got fed up with the filter recently so bought a tiny Eden power filter; as soon as I plugged it in the fish started acting strangely and overnight they all dropped dead;

possible theories

1. The strong current it created caused the poor buggers to swim their little hearts out
2. Lack of bubbles from the old filter caused water deoxygenation
3. It dislodged the algae growing on the artificial plants  which blocked their gills

anyway don't buy one 

[Kim]

 

I know the bubbles aren't supposed to oxygenate the water; the surface area is.  Otherwise your tank is too small for the number of fish, and a pump failure could suffocate them (rather than just messing up the bacteria in the filter bed).

I'll add:

4. Perhaps some fault in the pump, exposing the fish to an electric current, or releasing a toxic substance?

[Martin]

4. Perhaps some fault in the pump, exposing the fish to an electric current, or releasing a toxic substance?

who will ever know? I threw the thing on the floor when I got home so it's not going back to the shop 

[BrianI]

Did you keep some of the old  filter media to go in the new filter?

Sorry for your loss.   

[Vince]

I would suggest some sort of contamination.