The first question that should always be asked when planning a custom aquarium will inevitably be about how big it should be, as size will often shape not only the cost of construction and installation but also running costs and the number of fish required.

The size of the tank, therefore, will shape every other decision and typically cannot be reversed; you can change the fish, alter the pump and change the aquascaping, but once the tank is installed, the only way to change it is to dismantle the entire setup and start again.

This means that it is important to get it right, but whilst few aquariums will reach the bewildering size of Chimelong Spaceship in China, the current largest aquarium in the world, how large is too large, and indeed, how small is too small?

Why Are Small Tanks Problematic?

Besides the aesthetic limitations that come from a small aquarium, there are practical problems that a tank under 35 litres can cause.

Part of this is the limits it can impose on the number and types of fish you can hold in the aquarium, but a bigger problem is that smaller tanks are vulnerable to rapid changes in water quality.

This can lead to added stress to fish, which can cause health issues or problems with incompatibility.

Small tanks can also require more maintenance than one might expect, often needing more water changes than a slightly larger tank designed with biodiversity in mind might.

Another issue with retail, commercial and office aquariums is the effect of the outside environment is magnified with small tanks. Much like how typing on a keyboard can cause a glass of water to ripple, the hustle and bustle of a busy office can cause additional stress.

Whilst each fish has unique requirements, allowing at least 10 litres of water per inch of adult fish helps to ensure they have enough space to swim and avoids problems with water chemistry.

Why Can Large Aquariums Become A Problem?

Some people, including the owners of large water parks, subscribe to the notion that bigger is always better when it comes to aquariums, but this is not always the case.

In an ideal world, with an unlimited budget and infinite space, large aquariums are truly beautiful and can provide a wide range of aesthetic, mental health and productivity benefits.

However, most businesses looking at potential aquarium installations do not have the funds required to construct an aquarium that large or fill it with an ample supply of fish to justify the size. 

Even if they did, many do not have the space to store an aquarium of that scale or have the specialist maintenance infrastructure to keep the tanks clean and fish well-fed.

As well as this, filtration and pump equipment will naturally need to work harder and be maintained more regularly with larger tanks.

Finally, there is weight to consider; a 35-litre aquarium of the type that is just about large enough for most office settings can weigh over 45 kg once full, which means that larger aquariums need to be installed in areas with reinforced floors strong enough to hold them.

Location, Location, Location

Ultimately, placement will be the biggest factor in the size of your tank as well as its purpose, and it should be placed and presented as a central statement part of your room’s interior design.

This means that a larger aquarium in a bespoke stand or installation will provide greater and further-reaching benefits than smaller tanks on desks or stored on shelves.