How Fish Sink and Float

Science Buddies
Brief Description

Have you ever thought about why most fish never sink to the bottom of the ocean or float to the water's surface? How is it that they can stay so perfectly buoyant under water? You might be surprised to hear that most bony fish have a special organ to help them with that: a swim bladder. The swim bladder is a thin-walled sac located inside the body of the fish that is usually filled with gas. Besides helping the fish stay buoyant, it can also function as a sound producer and receptor or as an accessory respiratory organ. Wonder how a swim bladder works? Then do this activity to find out!



Svenja Lohner, PhD, Science Buddies
Resource Type
STEM/STEAM Activities
Delivery Format
In Person