All fish swim at very top of tank...gasping for air??

[TheChad]

Hi,

All fish in my tank are swimming at the very top of the tank. It's strange to see them all up there at the same time. It's not just swimming at the top, it's like they are stationary, and all trying to get air or something.

I think it only started happening after I put my canister filter in about 3-4 weeks ago.

Before that i was just using an internal power filter

[Merrilyn]

I would suggest you test your water immediately for ammonia and nitrites, both of which can be fatal. If you get a reading of either, do a 50% water change straight away.

Did you leave the old filter in the tank when you started using the new canister. Your tank could be going thru a cycle again.

The other thing that comes to mind is, gill flukes.

For the time being, add an airstone to the tank to increase the available oxygen, and maintain the temperature at around 28 degrees. The slightly cooler water will hold more oxygen.

[TheChad]

Thanks for that.
I did a check for both Ammonia & Nitrate a couple of days ago, but obviously didn't leave the tests long enough to see a real result.

Nitrate is at 1ppm and Ammonia is 0.5ppm so I guess it is these that is causing the fish to go to the top of the tank.
PH is 6.5

I did leave the older filter in the tank, in fact it is still there. Is it best to leave the spray bar on the canister filter? It doesn't seem to spray much. Or should i remove the spray bar and just leave the tube pipe into the tank?

I have added an airstone just now.

[Merrilyn]

Do daily water changes of about 20% for the next few days, until the readings of Ammonia and NitrIte are zero. A mature tank should always have a reading of nitrAte. That just means your bio filter is working. You remove the excess nitrAte by doing water changes.

Any ammonia or nitrite reading means that your filter is not converting all the waste produced by your fish, so cut down on feeding for a few days. That along with the water changes should see an improvement in your fish within a fairly short time.

If you don't see any improvement after a week, or if the fish begin to look worse, treat for gill flukes.