Many fish live in:
D) Rent-controlled Condos with an option to buy
If you answered B, schools, good work! Not all fish school, but many do, including cod, tuna, one fish, two fish, red fish, and even blue fish.
How do fish school, and why?
The most intriguing thing about schooling is how such large groups of fish manage to stay together as they zigzag through the water. Although fish rely on eyesight and hearing, many also have a special sensory organ called a lateral line that runs down the length of their bodies. This organ consists of tiny hairs that register changes in water pressure and so allow fish to sense movement in the water around them.
In some instances this allows fish to sense danger in the form of approaching predators. In a school, the lateral line system allows fish not only to see where their classmates are going but to instantly sense their movements and follow along.
As for why some fish form schools in the first place, a key reason is safety. Swimming alone, a single fish is easy prey for a predator. Swimming in a school gives each individual member a greater chance of not becoming a meal. Plus, from a distance a large school might appear to a hungry shark as something dangerous and not worth attacking.
Most fish might have small brains, but many are smart enough to stay in school.