Possible Mouth Fungus/columnaris Rainbow Fish

[DesperateDanio]

Help have 2 Rainbow fish which are in the same tank as the sick danio which died and they seem to have some cotton mouth oh no now after reading up on it am i right in thinking that i need to treat the whole tank and if so anyway i can do this with out damaging the biological filter pls advice on what meds and whether to treat whole tank no other fish showing symptoms but had a danio die for no apparent reason quite suddenly

Ammon 0
nitrite 0
Nitrate 20 - 30 ppm

need advice quick as pets at home shuts in an hour 8pm so i need to get meds and poss a filter for the other tank

 

[WILDER]

Answered on your other thread about meds.
All you need to remove is black carbon if you use it in your filter.
Increase aeration as meds reduce 02 in the water.

 

[DesperateDanio]

Thanks sorry for the 2 posts but wasn't sure if people had stopped looking at the other as the poor fishy had passed