An aquarium is not simply a glass tank with some water and fish in it, but a miniaturized eco-system that needs multiple components in order to thrive. Any successful build will therefore typically need the following mandatory components:

One of the most important decisions you have to make when starting a new aquarium is the choice of aquarium tank. There is a sheer endless amount of different aquarium tanks on offer and a lot to consider regarding material, shape, size, cost, etc. This article is intended to help you understand what the differences are and how you can make the best choice for your purpose.

Materials

When it comes to tank material, most aquariums can be classified into three different categories:

Material Price Clarity Weight Scratch Resistance
Float glass $ low high high
Optiwhite-glass $$ high high medium
Acrylic $$$ high low low

Float glass

Float glass is more common in older aquariums. The name Float Glass comes from the way it is produced (Float process). During the process the molten glass is poured into a pool of molten tin. As the weight of the molten glass is lighter then of the molten tin, the glass floats on top, hence the name Float glass. Float glass can also be found in (house and car) windows and mirrors.

Float glass is easy to identify: it has a green shimmer to it, especially noticeable on the edges or when looking through the glass at an angle. The green shimmer is due to the high level of iron in the glass.

Float glass was the first type of glass used in aquariums and is therefore most commonly used in older aquariums (it can still be found and bought today, though). The green shimmer is also the reason why it is not common in new aquariums anymore.

Optiwhite-glass

Optiwhite glass is also a float glass, produced with the float process. The main differences to regular float glass is the low iron level (<1%) making the glass appear extra clear / transparent with a very high light transmission. It is almost colorless and the green shimmer is not perceptible to the human eye. This makes it the perfect aquarium glass as it gives you a clear and pure view into your aquarium.

Once you had an optiwhite aquarium, you will probably not be able to go back to float glass. The green shimmer is too much of a visual distortion to ignore and the price difference is not too big.

Acrylic

Acrylic is made from fossil fuel based fiber and is also called plexiglass. The main differences to regular glass are its weight (at least half of the weight of glass), its high impact resistance (20 times higher then glass) and high optical clarity. The low weight makes it a popular choice for very large tanks that would get too heavy using regular glass.

The edges of acrylic aquariums are bonded together which makes the seams stronger and visually more compelling then in glass aquariums. Unfortunately acrylic glass is much less scratch resistant than glass, which has a huge impact on the handling and cleaning of acrylic aquariums. It is not recommended for beginners, as it requires some experience in handling (especially when it comes to maintenance) and is more expensive than its alternatives.

Rim vs Rimless Aquariums

Rim aquariums are the first aquarium build type ever used. The rims frame the glass panels and help keep them together, thus adding a layer of security to a tank. The rims protect the corners and the water volume pushes the panels against the rim.

On the other hand, the rim is a visual distortion and may distract from the beautiful view into your aquarium depending on the panel size.

That's also why rim aquariums are usually only used in very large aquariums holding several hundred gallons of water or more these days. Smaller builds mostly don't need the added security anymore and look nicer without the rim.

Rimless aquariums are the latest standard in the aquarium build industry. The method has improved over the last couple of years minimizing the silicone gap between the panels.

Rimless aquariums are just as safe and good as rim aquariums (up to a certain water volume). The main advantage is the clear, pure and uninterrupted view into the aquarium.

Lid vs w/o Lid

The choice between an aquarium with or without a lid is mostly based on personal preference. Nevertheless, it is always good to at least have the option of adding a lid when needed.

Many aquascapers like their aquariums without a lid in order to allow for easy access to the aquarium for maintenance or adjustments or because elements of the aquascape go above the water line.

However, not having a lid on the aquarium leads to a higher evaporation of water compared to an aquarium with a lid. This means you will probably have to refill water more often when not using a lid. It can also be a safety issue, as many fish species tend to jump out of the tank when startled or just generally jump from time to time and could fall out of the tank and die this way. Therefore it is advisable to check in advance if the fish you're planning to put into your tank are jumpy and generally keep a lower water level in a no-lid-aquarium to make it harder to jump out.

There are various option with transparent or steel finished lids.

How to add a lid to a non-lid aquarium

Acrylic aquarium lid hooks The easiest way to add a lid to a no lid aquarium is to buy an adequately sized (Plexi) glass panel and some metal / Plexiglas hooks.

The hooks can be attached to the side panels and have a horizontal surface with a silicone button on it on which the lid can be securely placed. In case your aquarium is to large, you can also section the lid to make it more workable

Black silicone vs. Clear silicone

Silicone is used to bond the edges of the aquariums together and make the tank leak proof. Both types of silicone are the same when it comes to functionality and the main difference is simply the color. The choice of silicone therefore mainly comes down to personal preference. But it's also important to keep in mind that the silicone will get algae over time, just like the rest of the tank. Depending on the color of your silicone, it might take more time/effort to remove it.

Therefore the main factor that should influence your decision of which silicone color to go for, mostly depends on how big of a gap there is between the panels. This gap doesn't have anything to do with the quality of the tank, but more with how it was built.

When the gap between two panels is smaller than 1 mm it is better to use the clear silicone as this gives the feeling of an almost seamless view and limits visual distortions. In this case, the surface for algae is so small that it can be easily removed, e.g. with a tooth brush or sponge.

Aquarium tank with black silicone bondings

When the gap between two panels is bigger than 1 mm, there will be a minimal visual distortion when looking into the tank. But since the gap offers a bigger surface to algae, the algae would be far more visible when using clear silicone and you would most likely end up with a green shimmer that is very hard or impossible to clean up completely. By using black silicone the green touch can be avoided.

Aquarium tank with white silicone bondings

Shapes

Aquariums come in various shapes. Most common are rectangular and square ones, but you can also find cylinders, hexagons, half cylinders with a bent panel, round ones, etc.

Again, this choice is based on personal preference, but we recommend to use a rectangular or square shape to begin with, as these are the most common shapes.

Depending on the purpose of your tank, you might also have an easier time with a specific shape. If you plan to do an elaborate aquascape it might for example be more straight-forward to use a tank with straight edges than a cylinder.

Placement in the room is another factor when choosing the appropriate tank shape. Long rectangular tanks with a translucent back panel are best suited as a room divider, half-cylinders and bowfronts are best placed against a wall and cylinders and hexagons can stand freely.

Please also keep in mind that the fish bowls often seen in movies or comics are usually way too small to responsibly keep fish in. Fish require at least a 10 gallon tank (without gravel and hardscape).

Size

If you are an aquarium beginner and not sure what kind of aquarium size to get, here are the two most important rules:

The first rule is …

The bigger the aquarium the more expensive are the one-time and monthly miscellaneous costs.

The second rule is …

The smaller the aquarium the more difficult to establish and maintain a working ecosystem.

The best aquarium size for a beginners therefore is between 10 - 30 gallons. The water volume is big enough to establish and maintain a balanced ecosystem, and there are reasonably priced tanks available to get started with in this size range. We'd always recommend choosing the biggest tank you can afford unless you're more experienced.

Unfortunately there is no international standard for aquarium sizes. The main three common categories are

  • gallons
  • liters
  • and the front size in cm with a letter behind it (e.g. 60 U or 90 p)

The sizes measured in water volume (gallons or liters) are pretty simple and easy to grasp. On the other hand they do not give any information about the width, length and height of the aquarium.

When aquariums are referred to as 60 F / P / U / XD / H , the "60" stands for width of the tank (60 cm in this case). The exact meaning of the letter depends on the manufacturer, but here are some of the most common uses:

The "F" stand for shallow height.

The "P" or "U" are the regular height.

The "H" or "P(XD)" refer to extra tall height.

Considerations for very large tanks

Glass beams

When buying a large aquarium it's beneficial to look out for tank models with glass beams as an additional safety feature. The glass beams hold the side panels together and help stabilize the tank this way. The longer the side panels and the more water you have in a tank, the more pressure is being applied to the middle area of the side panels. This can even cause a slight bend in the panels and make the tank burst in extreme cases / after a longer time. The glass beams help to stabilize those weak points. This is even mandatory from a certain size of tank, especially if you have a model without rims and only silicone bonding holding the edges together.

Static

A topic that is often overlooked but extremely important when planning a large aquarium is the static of the building / room you want to put the aquarium in. We recommend keeping these points in mind for every aquarium, but especially if it has a capacity of 40 gallons / 200 liters or more, as this means you'll be dealing with a total weight of more than 500 pounds / 250 kg.

One thing to consider is the load capacity of the floor. This is the maximum weight a floor is engineered to support and is measured in square pounds per square foot or kilograms per square centimetre. This information is usually only available in commercial buildings and needs to be obtained from the landlord or a structural engineer. You will also find some articles online explaining how to calculate floor load capacity yourself, but we do not recommend to make your own calculations and rely on expert advice instead.

Even large aquarium cabinets often only have 4 feet to stand on, which means that the total weight of the glass tank plus water is distributed on a very small area. Depending on your flooring and the exact weight of your setup this might mean damage to your floor, e.g. leaving visible indentation marks in a wood floor or make the tiles crack. To circumvent this, we recommend placing the cabinet on a weight leveling board so that the weight is being distributed evenly across a larger surface area.

Pro-tip: Always make sure to place a large tank next to a load-bearing wall in a room, either parallel to the wall or very close to it. This is due to the load capacity of the floor being higher the closer you are to a load bearing wall, while it is lowest at the center of a room.

Conclusion

The most common mistake for beginners is spending money on a small aquarium instead of going bigger straight from the start. Smaller aquariums may seem cheaper and easier to get started with, but they are harder to maintain and much more limited when it comes to choice of plants and livestock. Many beginners therefore quickly realize that they should've gotten a bigger tank to begin with and face double the costs when upgrading. Instead of buying the equipment twice it is better to invest the total amount into a solid first set up.

Personally we prefer and suggest:

  • rimless
  • optiwhite aquariums
  • with a minimum capacity of 20 - 30 gallons,
  • a lid
  • and transparent silicone seams.

Below we have added a few companies to give you a good idea

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