Traditional aquariums were made of glass, however advances in technology have now given fish keepers the choice acrylic aquariums or glass ones.
You may be unfamiliar with this new type of tank, so there some points to consider when deciding which type you want.
An acrylic tank would be around half the weight of the equivalent glass version. This is great for when you have to move the tank around you may also save money on delivery if you have your tank custom made. However you should remember the bulk of weight of an established aquarium is not the tank itself but what goes inside it, such as, water, rocks, sand and equipment. It would still be advisable to seek professional advice if you are planning on putting an acrylic tank of over 200 litres on anything other than the ground floor of a building.
Due to the way in which acrylic aquariums are made they are one continuous piece of material whereas glass tanks are made of several bits of glass bonded together with silicone. The points at which the glass is joined are the weak points of the aquarium and therefore acrylic has to be stronger because it lacks joints.
However it would be wrong to say glass aquariums are flimsy and will fall apart and need replacing after a couple of years. The last tank I bought, which was glass, came with a five year warranty and at the time I was concerned that I would have to replace it after 5 years. I now understand the warranty was really aimed at the equipment that comes with the tank, such as the light, filtration and heating systems. I have had my tank about ten years now and it shows no sign of weakness or age.
I do not worry that the silicone which holds my tank together will fail, but I do worry about something smashing in to it and cracking the glass. It would be near impossible to smash or crack silicone, meaning it would be a better choice for busy environments, such as a bar or night club.
Overall I feel glass offers a much better viewing experience. Firstly, Plastic scratches much more easily, you will need to be much more careful when cleaning algae off the glass.
Overall time acrylic tends to acquire a yellow tint, meaning the view of the fish is not as good. Manufactures claim that due to improved technology new tanks will stay crystal clear for much longer; we will have to wait till these tanks get old to see if their claims are true.
Due to the way acrylic tanks are made there is no limit to the different shapes and designs available. There are many manufacturers who will custom make and install an aquarium to your exact requirement, which makes them a very stylish option.
At the moment glass tanks are much cheaper than acrylic aquariums. However with technology always improving this could change. Plus, demand has a way of driving price down, if enough people want one the price will probably come down.