Saw shark

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

In
After the player has donated a Saw Shark to Blathers, it will appear in the section for fish and 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."

In
"As you might expect from the name, the saw shark is a shark with the head that resembles a saw. This unusual appendage is used both to dig potential prey out of the sand and as a weapon against said prey. Given that, it seems like a more appropriate name would have been 'shovel-sword shark,' eh wot?"