How do fish blow bubbles?
With their gills.
The bubbles are a bubble nest. Male bettas are the ones that take care of the kids in betta society. They blow the nest and that usually means he's happy or ready to reproduce. They also sometimes blow them when the composition of their water changes or their is a barometric change in air pressure. It doesn't always mean they are ready to be parents, though and sometimes perfectly healthy males won't blow them.
some dolphins lyk chase fish on a bank and then the fish all roll on it and then the dolphin launches itself on the bank and eats t he fish some dolphins surround the fish and blow bubbles in a circle around them, which will make the fish panic and jump out of the water and into the dolphins mouths. theres probz other ways but idk them! x
Aquatic crabs held above the water will produce bubbles through respiration. They draw the air into the space between their claws and shell (arm pit area essentially) and blow it out through their mouth. The protein in the water keeps the bubbles formed from bursting quickly, thus they "blow bubbles".