The Scent of Danger Makes These Fish Hulk Out 
By Susan Cosier US Source: hakaimagazine 6/5/2021

Gilthead seabream swim back and forth in their tank, the yellow markings between their eyes that they’re named for flashing as they glide by. Carlos Díaz-Gil, a graduate student at LIMIA, the marine research and aquaculture laboratory of Mallorca in Spain, adds a few ice cubes to their tank. The ice is made of water from a neighboring tank containing black scorpionfish*, one of the seabream’s feared predators. Díaz-Gil knows that the scent of the scorpionfish, just a trace of its existence, will likely cause the seabream to change in surprising ways.
 

After a month, Díaz-Gil kills a select few seabream and measures them. The fish’s bodies have gotten deeper—bigger from back to belly—and more difficult for black scorpionfish to swallow, expanding in what appears to be a natural defensive change.

 
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