Mine started nipping a lot after I fed them by hand. I've never had one bite quite that much, though! Usually, the female nips and darts away. The male will bite and try to shake me back and forth like a shark. Either way, it's just a tiny pinch for me! I'm guessing your girl was eager for food, too.
10 gallons, petco king and community fish
1 x 5.5 gallons with shrimp and plants
1 x 5.5 male veil tail with plants