Newly discovered lymph hydraulics give tunas their fancy moves
Long-overlooked anatomy raises fishes’ fins for zigs, zags and tight turns
![Big tuna](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2017/07/072617_SM_tuna_main.jpg?fit=860%2C460&ssl=1)
FINTASTIC A sickle-shaped fin on the back of a tuna and one underneath contain shape-shifting systems that scientists have just discovered.
Monterey Bay Aquarium