Do a partial water change because you might have overdosed the medication.

Increase aeration/ surface turbulence when using medications because most of them reduce the oxygen in the water.

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To work out the volume of water in the tank:

measure length x width x height in cm.

divide by 1000.

= volume in litres.

When you measure the height, measure from the top of the substrate to the top of the water level.

If you have big rocks or driftwood in the tank, remove these before measuring the height of the water level so you get a more accurate water volume.

You can use a permanent marker to draw a line on the tank at the water level and put down how many litres are in the tank at that level.

There is a calculator/ converter in the "FishForum.net Calculator" under "Useful Links" on the right of this page that will let you convert litres to gallons if you need it.

Remove carbon from the filter before treating with chemicals or it will adsorb the medication and stop it working. You do not need to remove the carbon if you use salt.