I added golfish with angels, once. I figured the glofish would be ok, and they were for several weeks. The angels got several more weeks of growth on them, and snacked on the glofish. The angels were a little bigger than half dollar body size. I really doubt the angel is stressed bu the glofish, it may be the other way around.
How long is like forever? I've had adult angels go for a good 4 weeks with no food and survive.
How long is like forever? I've had adult angels go for a good 4 weeks with no food and survive.

. It shouldn't cause any stress as long as you don't leave the water level like that for too long. Unless you have some sort of substrate/rock that is buffering the water the only reason why I could think the pH is different is because of the C02 in the tap, which is way I say you need to age your water before you do the change. Most of the C02 should gas off in as little as 20 or 30 minutes, but you will need to make sure you use dechlorinator and the temperature matches. If you leave it for 24 hours then you can normally get away without any dechlor, but I would still recommend adding a portion of what you need to neutralize heavy metals. I am not sure if chloramine will evaporate either.