What Is The Best Size For A Saltwater Fish Tank?

When it comes to setting up marine aquariums, there are many things to consider. The aquarium will need a careful balance of heat, light, filtration, and water composition to remain healthy and sustainable. One of the very first things to decide is how big your tank should be. Here are some points to bear in mind.

Smaller does not mean easier

Novice marine fish keepers may think that a small tank will be easier to maintain, but in fact this is not the case. Because a marine tank is quite a delicate ecosystem, it needs a careful balance of water pH, nutrients, lighting, livestock and food to allow it to function happily. The environment is sensitive to even small changes in any of these elements.

For example, it might be easy for a newbie tank owner to accidently overfeed the fish, or set the wrong intensity of lighting. A larger tank can more easily withstand the impact of these mistakes, whereas they may prove fatal in a smaller tank. 

This is because the larger volume of water slows down and dilutes the effect of the change, whereas in a smaller tank, the abrupt change in climate may be too much for some of the more sensitive livestock to deal with. 

Cost effectiveness

One of the arguments for buying a smaller tank is that it is cheaper, and you will need less energy and equipment to run it. However, as we have seen, this may be false economy if it will be more prone to accidental contamination, and thus the livestock and water will need more frequent replacements. 

Another factor is that marine tank owners tend to want to upgrade to a bigger size after three to five years of successful aquarium keeping, if they have started out with a 75 or 80 litre tank, for example. In the long run, this is more expensive than buying a bigger tank in the first place. 

Where will the tank go?

Another question to consider is where the tank is going to live. It is critical to place it correctly, so the size of tank you buy may be dictated by its location. Remember that it is not just space for the tank you will need, but also for the equipment, including the filters, lighting, and heating systems, which will need to be safely plugged in to a wall socket.

The tank should be placed away from bright sunlight, so directly opposite a window is not a suitable place, as it will prompt algae growth. Conservatories, summer houses, and so on, are also too bright. These types of spaces are also prone to temperature fluctuation, which will be harmful to the safe maintenance of the tank’s environment.

For this reason, the tank should also not be placed near to a radiator or other heat source. They are heavy, so they need to be placed on a strong and stable flat surface.

So, what is the ideal size to start with? There are no rules, but a tank of at least 80-100 litres is regarded as the most manageable minimum size for beginners.