Adaptation

When the goliath tiger fish lies in wait to ambush its prey, it uses its internal air sac to "catch" or sense vibrations that their target makes, and then send them via a unique bone to their ear. Once they sense the vibration of prey, they used their streamlined body structure and powerful muscles to dart towards it and catch it with their long, sharp teeth. 

Info Source: http://webecoist.momtastic.com/2010/11/02/armed-to-the-teeth-africas-terrifying-goliath-tigerfish/

Image Source: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjfJ-V9X7XSQVB_gqlb8OMLqhCDByt5Gz7FrwoLdyDDX74R4yyYT53ORAYUP6YSzqzFsXLRUyCVOF3_zEYTqz67l3XuTgiMr331AV7umZSqFvGW9raz-aAD27hhlGNs2hS5FKKvEukcF24_/s1600/Screen%252Bshot%252B2010-10-26%252Bat%252B6_58_44%252BPM1.png