- Communication: Some species of fish use bubble streams as a form of communication. For example, bubble nests serve as a visual signal to attract potential mates and protect the eggs during the breeding season.
- Nest building: Certain species, like the Siamese Fighting Fish, also blow bubbles to construct nests at the water surface. These bubble nests serve as a place to deposit and protect the eggs during incubation.
- Respiration: Fish, like mudskippers, blow bubbles to breathe when surfacing from the water or in low oxygen environments. This behavior is particularly noticeable in areas with stagnant or polluted water, where they need to supplement their oxygen intake.
- Defense and Distraction: Some fish, like the Archerfish, form bubbles as a defense against predators. They create a bubble net that disrupts the water's surface tension and acts as a barrier, making it harder for predators to target them.
- Hunting: Bubble-blowing can be part of a hunting strategy. Some fish species, such as the Blowfish or Pufferfish, can expand and inflate their bodies, creating a large, intimidating appearance. This, combined with the release of bubbles, serves to deter potential predators or startle prey into exposing themselves.
- Spawning and reproduction: Nest-building species create bubbles to make foam nests where their eggs can stay protected and have a better chance of survival.
- Oxygen regulation: Some fish blow bubbles to regulate their buoyancy. By adjusting the amount of air in the swim bladder, they can effectively ascend, descend, and maintain a specific position in the water column.
- Feeding behavior: Some carnivorous fish, like sea bass and scorpionfish, may create bubble curtains that help direct their prey, making them easier to catch.
- Bubble fishing: Certain archerfish species spit out a stream of bubbles on the water's surface to dislodge insects and other small prey hiding beneath.