Hi
I'm a little worried about my 200L community tank, Its a well established tank that has had no problems , its a little over stocked but nothing major and well filtered with a Eheim external filter, i also run a air wall which aerates the tank as well as looks nice.
Yesterday i did a big change around in the tank, adding a peice of wood and 1 extra stone, nothing major but did do a 45% water change at the same time a little excesive i know but there you go.
Last night they were all fine and up till late this afternoon all was fine , i've just noticed at about 9pm a lot of the fish are at the surface and some breathing heavy, I've tested the water and its almost perfect , to withing a wisker .
Apart from the water change i can't think whats happened , I've increased the air flow via the pump.
Any ideas guys ?
Should i be this worried ? , its just out of the normal behaviour