Select the amphibian.

 - black howler
 - red-headed poison frog
 - salmon
 - thresher shark
A red-headed poison frog is an amphibian. It has moist skin and begins its life in water.
Poison dart frogs come in many bright colors. Their bright color warns other animals that these frogs are poisonous.
A black howler is a mammal. It has hair and feeds its young milk.
Howler monkeys have loud calls, or howls. Their calls can be heard over three miles away!
A thresher shark is a fish. It lives underwater. It has fins, not limbs.
A thresher shark has a long tail. It can use its tail to hit and stun prey.
A salmon is a fish. It lives underwater. It has fins, not limbs.
Unlike most other fish, salmon can live in both fresh water and salt water.