Originally Posted by Myates
Almost dead bettas in those cups will make a bubble nest too.. happiness doesn't really apply to bubble nests.. but it's something we like to believe :)
Bubble nests are created by the males using their saliva- it's created out of instinct, whether it's breeding, territorial or even a weather system coming through will cause them to create a nest. Some males are prolific nest makers and will make them all the time, others will only make them under certain circumstances. Some of mine will make them when it rains, others must have an IAL or oak leaf in the tank to make them, etc.
Many, many years ago, my best friend's sister had a Betta in an 8 oz cup and hardly ever changed the water, it was so dirty, you could hardly see the fish, yet, on the top of the water was a huge bubble nest. When she did change the water, you could tell that he was sick because his fins were so clamped they looked like strings, but as soon as she put him back in his cup, he'd start making another nest, until it overflowed out of the cup.
My male only makes nests when a storm is coming through. The bigger the nest, the bigger the storm. He made a huge one yesterday, and promptly rebuilt it after I changed his water, and we're expecting a huge snowstorm starting tomorrow and possibly lasting until Sunday.