fish
I do not know of any mammal (mammals are the only animals to have hair) that has fins (fins are the preserve of fishes), but a sea-lion is an animal that is covered in hair and has "flippers".
a fish
A reptile?
The animal that has two pairs of fins is the bony fish, specifically those belonging to the class Actinopterygii. Most bony fish possess a pair of pectoral fins located on the sides of their bodies and a pair of pelvic fins located further back, both of which help with swimming and maneuverability. These fins are essential for balance and stability in the water.
4 fins
2 fins
Animals that use fins to move are whales, dolphins, sharks, and various types of fish. A fin will generate thrust and propel the animal through the water.
seven fins are on a sailfish.
there are none.
These are structural. They're to do with an animal's structure. Behavioural means to do with how an animal behaves, or responds.
There are two Dorsal fins on a perch. The anterior and posterior Dorsal fins.
Paired fins in aquatic animals help with both movement and balance. They provide support and help the animal steer and change direction in the water. The paired fins work together to propel the animal forward and maintain stability while swimming.