Is adding sick fish into a planted tank dangerous?

[batlovesowl]

Hi,

I've just set up a planted tank, after a few days I bought a packet of cardinal teras. Hence putting them into my tank, only to find out that one of it has a pop eye 4 with white spot.

I've only manage to take out the pop eye and 1 white spot...

It was a stupid mistake... that i forgotten to quarantine the fish first for some time..

If my fish passed away one by one after a week do i need to do a 100% change of water?

[vinz]

Theoretically, 100% is not possible as the surfaces of the tank, plants, wood, etc will still be wet and there will still be pathogens in the water. But it will reduce a lot of it.

Also, for white spot, there is a part of the cycle where the spores will drop into the substrate... hence, you can't remove them effectively either.

But a 100% water change will set your cycling back to practically square 1. If you do so, take the following precautions:
1. Put the "fresh" tap water in a bucket and treat it with anti-chlorine/chloramine, then pour into tank.
2. Repeat until the tank is full.

Why? Because a full tank of "fresh" tap water has enough chlorine/chloramine to wipe out your fledgeling filter bacteria colony.

Since you are doing 100%, it means that you will be removing your fish. Might as well quarantine them until you are sure non of them have picked up either diseases.

What you can do for white spot is salt the tank. Search the forum, the dosage is here somewhere.

For pop-eye, I can't remember the treatment. Search the forum. But note that a lot of medication have adverse effects on plants and invertebrates.