I tried feeder guppies with my 2, just put 5 in the tank, there's only 2 left as they don't seem to have too much of an interest in them, although it's closing on australian summer here, so temperatures are rising. I've added a bottle of frozen water that I'll change every day to try and keep the tank cool, but I actually found one guppy in a mucas coat, like it had been vomited back up! What does this mean? Does it have to do with the sudden high in temperature?