"Neutral buoyancy" means that an object or a person can float in water without sinking or floating to the surface. It stays at a certain level in the water, neither sinking nor floating upwards. Full definition
Astronauts can train for space missions in underwater environments like the enormous Neutral Buoyancy Laboratory, located in NASA's Johnson Space Center. (discovermagazine.com)
THOMAS STRUTH Neutral Buoyancy Lab, JSC, Houston, 2017 Chromogenic print Image: 79 1/2 x 149 7/8 in. (artspeak.nyc)
Sailors eye ball, sea pen, Christmas tree, worms very often mantis shrimp, Moray Eels, Spanish Dancers and crocodile fish but watch your hand for stinging hydrozoa by achieving neutral buoyancy. (safaridivebali.com)