He also had 13 aquariums for saltwater animals and 33 aquariums for freshwater animals. Each aquarium has 31 animals in it. How many saltwater animals does Tyler have?
There are 13 aquariums for saltwater animals. 
Each aquarium has 31 animals in it. 

We want to find out how many saltwater animals Tyler has in total. We can do this by multiplying: 

13 x 31 = 403

Tyler has 403 saltwater animals.