What is a bubble nest?
Male beta fish will often build bubble nests when they are happy or content. These may look like large masses of floating bobbles at the top of the tank. This is nothing to worry about and is perfectly normal. Betas take in surface air and move over under his nest and place a single bubble. After many, many bubbles, they can create a large, thick nest. However the real reason a male beta fish will build a bubble nest is to harbor and protect the female beta fishes eggs. the male will carry each egg up into the bubble nest and place it in very carefully.
