Most modern fish tanks and aquariums are made from acrylic, largely due to the fact that acrylic is softer and more flexible than glass and can be easily molded and formed into a wide variety of shapes. Glass aquariums tend to be rectangular in shape because of the rigidity of glass. It is also possible to cut through acrylic to provide a filter overflow system, but this is not possible in a glass aquarium. Although a rigid glass aquarium has the advantage of requiring less structural support. An acrylic aquarium will require an aquarium stand to support the bottom of the tank from collapsing under the weight of the water. There are many types of aquarium stands available in different sizes and shapes to suit the modern and varied designs of acrylic aquariums. Alternatively, a few acrylic fish tanks are made with a substantially thicker acrylic bottom than the rest of the aquarium so that an aquarium stand is not necessary.
An acrylic aquarium provides a clearer view of the interior of the fish tank as it does not refract light as much as glass, when light passes through water. Acrylic also has a transparency rating of 93% which is superior to the quality of viewing provided by a glass aquarium. The biggest drawback cited against an acrylic aquarium is that it is so easily scratched. Acrylic can be scratched by a person’s clothing or bag brushing against it, whereas glass is very difficult to scratch. To deal with this, there are acrylic polishing kits which can simply buff out the scratches on the outside of the tank. (They cannot be used inside the aquarium because of toxic residue). It is very important to use acrylic safe tools when cleaning your aquarium and to ensure you do not pick up any pieces of gravel in the pad when scrubbing the inside.
Other considerations are the substantially lighter weight of an acrylic aquarium as opposed to a glass one, which make it much more portable, and the additional strength of acrylic. Acrylic also insulates 20% better than glass which reduces temperature fluctuations, maintaining a more stable environment for fish. It is important to note that acrylic is flammable so do not set burning candles on or near an acrylic aquarium.
There are advantages and disadvantages with both acrylic and glass aquariums and it depends on the aquarist to weigh up the pros and cons. You will, however, find that the majority of aquariums are now acrylic and if you want an aquarium that is any shape, other than rectangular, you will have to chose an acrylic option.