Fish bladder function: Science Education for the Early Grades › Forums › Volume Two › Learning Progression “A”: NATURE OF MATTER › Lesson A-15. Will It Sink or Float? Concept of Density and Its Measurement › Fish bladder function: This topic has 0 replies, 1 voice, and was last updated 2 years, 6 months ago by Bernard Nebel. Viewing 0 reply threads Author Posts August 15, 2018 at 8:08 am #7149 Bernard NebelKeymaster Using simple diagrams and explanations, the following site explains how fishes can alter their density to rise, sink, or maintain their position in the water. It goes on to describe variations on the theme. http://aqua-fanatic.blogspot.com/2011/05/what-is-swim-bladder.html Author Posts Viewing 0 reply threads You must be logged in to reply to this topic.