Male zebrafish sex tool stops fin regeneration
![](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2013/10/zebrafish20fins_860.jpg?fit=860%2C460&ssl=1)
SEX OVER SURVIVAL Male zebrafish have spiked structures on their pectoral fins (shown), which help them have sex, and also make a protein that blocks fin-tissue regeneration after injury or amputation.
Kang et al/Developmental Cell 2013