after treating the tank for fungus and also with aqualibrium as said in other thread things seemed to be looking up.
yesterday i come home from work and the fish had rapid gill movements and were darting around - sign of water poisening/quality i presume.

So i did a 40 % water change and the fish seemed to be breathing normally.
I come home today and they are bad again, there is a film on top of the water and some large bubbles. Also there is a bit of a smell coming from the water.!

AAAH what is happening to my tank??