There are basically two types of aquariums on the market today, glass and acrylic. Each type has advantages and disadvantages. Glass aquariums are less expensive in the small to medium sizes and are more readily available. Also, glass tends to be more resistant to heat, and does not scratch as easily as acrylic. The downside to glass aquariums is that they are considerably heavier, and have silicone seals in the corners that need replacement with time.

There is a broader range of design possibilities with acrylic. Acrylic can be bent and molded into just about any shape imaginable, and is considerably cheaper in the large size aquarium. Besides the design possibilities, acrylic is clearer than glass, and it can be repaired easier if it does get scratched.

In both types of aquariums, there are specialty systems available. Some of these systems include the complete filtration either in the hood or the back of the aquarium. Other systems, like the "reef ready" aquariums have the overflows for the filtration built into the back corners of the aquarium. When comparing different aquariums, it is important not only to compare prices of the different units, but also the quality of craftsmanship and especially the warranty periods that are included with the system.