Most fish tanks are made of either glass or acrylic. Ever wondered which material is better? Let’s find out.
Many people don’t know what the difference between acrylic and glass fish tanks is – except that the acrylic tanks are usually more expensive. We are used to thinking that higher price equals better quality, which is why many people think that the acrylic tanks are better. This is not necessarily true. Both glass and acrylic tanks have their benefits and their drawbacks and depending on your specific set of circumstances you should pick one or the other.
Glass vs Acrylic
| Glass | Acrylic |
| Very difficult to scratch. | Highly scratchable. You will have to be extra careful, use acrylic safe scrubbers and acrylic polishing kits. Of course, acrylic is also easier to repair when it is scratched. |
| Glass is heavier than acrylic. A glass tank will often weigh 4-10 times as much as an acrylic tank of the same volume. | Acrylic tanks are lighter than glass tanks. However, remember that the majority of the weight of a complete tank is the water and decorations, not the tank itself, so you will not save a lot of weight by using an acrylic tank rather than a glass one. |
| A sharp impact will crack or shatter a glass tank, or at least one of its sides. However, this is not an every day occurrence. The force required to break a glass tank needs to be pretty significant. | Though a very sharp impact will crack or shatter a piece of acrylic, the amount of force needed for this damage is far greater than it is with a glass tank. |
| Not too many shape options. Glass is relatively rigid and brittle. Because of this, it is difficult to make fish tanks from glass that are not rectangular in shape. Also, when glass is curved, it has a tendency to bend light, making things on the other side of the curved glass appear larger or smaller than they really are. | Acrylic is easily molded and formed into almost any shape. Acrylic also has less of a tendency to distort things that are behind a curve. |
| Glass can support considerably more than its own weight over distances. Because of this, glass aquariums can be kept on stands with an open or incomplete top with little or no risk. | Acrylic tanks require a stand that will support the entire bottom of the tank, or else the bottom of the tank may pull away from the seams under the weight of the water. This is not true in acrylic tanks that have a substantially thicker bottom than would appear necessary. Also, acrylic tanks require much more support across the top of the tank to keep the acrylic from bowing apart and either splitting seams or spilling water. |
| The materials required to build a glass tank will be thicker than those required to build an acrylic tank. Though tempered glass does not need to be as thick as non-tempered glass for the same size of tank, the tempered glass will still be thicker than the acrylic necessarily would be for the same tank size. Also tempered glass cannot be drilled to accommodate any filter system designed to use an overflow. | Acrylic does not need to be as thick to support the same water volume as glass does, and any acrylic tank can be drilled to accommodate an overflow system. |
| Glass has a different index of refraction than water which results in a slightly distorted image. Colors are not quite true, position is not quite accurate, size can be distorted slightly. The thicker the glass is, the more pronounced these errors become. This means that in tanks with particularly thick walls, the fish can be significantly distorted. However, most home and office aquariums, even large ones, are not large enough for this to make a significant difference. | Acrylic has nearly the same index of refraction as water. Because of this, the only distortion you are likely to see is that the fish is slightly misplaced, but the size and color are true. |
| Glass maintains its clarity over time. The glass in a new tank will match that in an old tank. | Many types of acrylic will yellow with age, particularly if they are kept under a full spectrum light or are exposed to direct sunlight. This is a normal chemical reaction in the materials that the acrylic is made from. Though this is getting much better, this is still a possibility. Also, because the acrylic is so fragile, it is very likely that you will be viewing your fish through a haze of scratches that will only get worse over time. |
| Glass is easier to ship and requires fewer specialized tools to work with, so glass tanks tend to be less expensive than acrylic tanks. | Acrylic tanks tend to be more expensive than glass tanks. This is not necessarily because the acrylic is better than the glass, though in some ways it is (and in others it is not), but more often is due to the shipping costs. In many cases it will cost less to make the acrylic tank, but after the first three or four have been too severely scratched in shipping to be sellable the cost to the aquarium owner is much higher than the glass tank. |
Bottom line, which is the better choice, glass or acrylic?
If you want a traditional rectangular medium-sized aquarium, if you don’t want to mess with the scratches, and you are not worried about sharp objects shattering the tank, then glass aquarium will be the right choice for you, plus it will save you some cash. However, if you are setting up a very large tank – 500 gallons or more – or you are interested in a tank that is not rectangular in shape, you will probably want to consider acrylic.
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