if you watch videos on the Great Barrier Reef corals are at the mercy of the tides. A lot of colonies end up out of water for hours at a time. They get blasted by direct sunlight too. Just imagine that, it really takes a lot to kill these things. I mean we can literally break them in two and they keep growing. So no, your absolutely fine. When i do my fragging i do it outside and in the sun. I like the extra light and heat to glue. Also when they slime up i expect them to be in a defense mode, which means to me.. in theory.. They are less stressed when messed with.