Hello

Me and my girlfriend have just got a 25 gallon tank and got a couple of fan tail fishes 3 weeks ago. We have just got back and found one dead and the other one is looking ill. We have treated the water for chlorine and have a filter in it which we bought new.

I am just wondering what we have done wrong?

I was wondering if the pump was too powerful? They always seem to be fighting it? We got the fish where from Pet smart and where healthy when we got them

I would like some help as we would like to get some more without them dying?

I hope someone can help

Thanks

Your aquarium has not yet had enough time to cycle.
Toxic levels of pollutants build up in the water
And can cause fish to become ill.

Please read about The cycle of an aquarium here.

If your fish are fighting to swim, then the pump may be to powerful
For the size tank you have.
What size pump is it?

Do you have a way to test your water?

Kae