Setting up and caring for the coral aquarium, or reef aquarium is a task that requires a bit of knowledge before starting. There are some steps to take when setting up a new coral aquarium. The process may seem to take a long time, and because of this, many people opt to use fake coral instead. However, the time spent waiting will be well worth it when you are later able to display your own coral aquarium. Although labeled as a shark because of their dorsal fins, these creatures are much smaller. They usually grow to be about a foot long. They will still need a larger tank with plenty of space, because they too will have a cruising nature. These fish, like true sharks will eat just about anything that will fit in their mouths. Filters can be complicated. Do a lot a research to find out what type of filter is suggested for the fish that you choose. There are filters that go beneath the substrate in the bottom of the tank, as well as filters that attach to the side of the aquarium. They also vary greatly in price. It is not necessary to buy the most expensive filter when setting up a basic freshwater aquarium. When cleaning your aquarium, be careful not to use paper towels, and harsh or abrasive chemicals, as they can scratch the acrylic surface of the aquarium. Always use a cleaner specifically labeled safe for acrylic. Use plastic or rubber scrubbers, rather than metal to clean the sides of an acrylic tank. The other thing that set catfish apart from any other fish is the fact that they have no scales. They also possess a strong, hollow ray on their fins that a stinging protein can be emitted from if the fish is irritated or in danger. The most common catfish found in aquariums are the armored catfish. This group is smaller in size than other types of catfish and make a great addition to an aquarium. The sides of the aquarium should be scrubbed regularly to remove an algae build up. Again be careful not to disturb the fish. Wash your hands thoroughly before and after handling the aquarium. Lastly, check the manufacturer's recommendation on filters and change them accordingly. Filters collect any fish waste or left over food.