Saw shark

The Saw Shark (ノコギリザメ, Nokogirizame) is a fish that can be found in the ocean from June until September from 4 pm to 9 am in. It has a large shadow with a fin and can be sold for 12,000 Bells.

Donating in New Leaf
After the player has donated a Saw Shark to Blathers, it will appear in the section for fish and deep sea creatures, specifically in the large tank in the north-eastern room.

"Saw sharks got their name from their long head lined with spikelike teeth much like a chain-saw blade. Sensors located below their mouths detect prey as they press their flat bodies against the seabed to search. They will sometimes swing their 'saws' wildly amid a school of fish, catching any that are struck."