Thank you all for your responses. They are really appreciated, as of now my
news are not so grim, I lost two fish. Last night after what happened I took
one of the Yellow Labs that was floating upside down by the filter intake
and put him in a small hospital tank. Today back from work the little fellow
seems to be recovered, he's swimming around the tank and seems a lot better.

I should have done the same with the other two but they were difficult to
catch and I didn't want to chase them around and stress them more. The one
is definitely gone, the second's gills are still moving but he looks bad, I
now have him in the hospital tank as well. I have read somewhere that
sometimes they come back even after they have stayed motionless for a while.
Not sure if there's any truth to that.

After reading your posts all day I realize that you all make some excellent
points.

I too was not certain as to whether or not it was ok to use the python to
fill the tank as opposed to a bucket of water that gets prepared first. But
I figured many people use their python to fill their tanks and I have in the
past also without an incident. I wasn't sure if adding the water treatment
was supposed to be before adding new water or during, I figured during would
be better.

The more I think of this the more Bitey's comment makes sense. At first I
thought it may have been pH shock to the fish that did it. But I was puzzled
indeed by the many little bubbles of air everywhere on the tank. On
decorations, glass, even on some fish. At that time I thought it was a good
thing thinking that I aerated the water stream enough when I was filling the
tank - I read somewhere that some of the chlorine escapes by having the
water come in under pressure and slash vigorously on the surface - in the
past I used to add water in a much slower rate.

I know think a pH shock should have come slower to the fish, but I'm
guessing here. I just checked the pH and it registers at typical levels, so
either it shifted in 24 hours time or it was ok to begin with. I was not
aware of "gas emboli" the way you described it one bit, but it almost sounds
like the 'bends' with divers. Is this a correct analogy? This is great
insight for all of us with tanks I think. I would have never thought of it.
The rest of the fish seem to be doing fine now in the tank. The pl*co did
not seemed phased at all but the cichlids felt it big time.

Will there be any future side effects from this ordeal in your estimation?
If I was to use a python to fill a tank is there a way to avoid this or
should I just skip to a water pump and a bucket?

Sorry for the long message but I feel that we all learned something here, I
certainly did and I thank you again all for your time.

Regards

Steve