help,new to web site ,does anyone no if to many tiny little bubbles in tank could wipe out a group of guppies about 60 . They where happy for three years until i moved recently to a new town with different tap water,i had never had air bubbles before now ,the funny thing is i bought 2 new fish when the group was down to about 20 and they are still alive but all the rest are dead ,there is about 3 different generation of babys and as soon as they get to teenager size they dye ,did all the usual stuff,water levels and white spot etc nothing changed,the only thing the fish all do before a slow 2 day death is there top fin goes down and they go a bit pail and swim in one spot at top of tank,also on acasion but not always a white poo comes out.(and its not a worm)
Im from Australia and my tank size is a 65litre water trickles from above any ideas would be great.

Bubbles wont kill the fish. My one tank is full of them.

Two things I think of is 1) is it possible they are dying from old age? and 2) when they interbreed too much the fry develop more problems. I had a couple that were so interbred that their fry would die before they hit adulthood. Maybe its time to get a new stock going?

It could also be the water itself. Maybe its so different the fish cannot handle it? Are the 2 new fish from the area you are in now? If so, they are used to the water chemistry.

Also, your tank is about a 16 gallon? If so, 60 fish in that is waaaaaay too many!

Make sure the water is always up to the top so that the filter water flows in, not drops in. If the tank is not full, the water from the filter will drop in creating tiny bubbles.