Nano Reef Aquariums: What Are They?

Nano Reef Aquarium – What’s that? From looking at the wording you may have come to the conclusion that small has something to do with it. You may have even seen one of these small aquariums at a local fish store and been curious!

A Nano Reef Aquarium is a saltwater aquarium usually under 30 gallons volume with filtration and aquarium equipment on a smaller scale. With careful coral, invertebrate, and fish selection, a miniature coral reef can thrive in a small aquarium.

Nano aquariums can make a great entry-level reef tanks or as a nice addition to a child’s bedroom if you wish to get them started with the responsibility of pet ownership.

Just because you have a small aquarium does not mean it has to be a boring aquarium!

Are There Different Types of Nano Aquarium?

Just like the larger aquariums, nano aquariums can come in all sorts of designs and setups to cater to not only budget, but the style the consumer is looking for.

Some of the most popular types of nano aquarium are:

Glass Only Aquariums

This is the simplest form of aquarium. It can be with or without a stand and canopy and is usually the cheapest of them all.

These types of aquarium can be easy and cheap to set up but all the equipment will be on display.

All-In-One Aquariums (AIO)

Fluval Sea Evo XII Large

By far the most popular of nano aquariums. The AIO aquarium comes with an integrated filtration area built into the rear of the aquarium.

This allows for all the equipment to be hidden to allow the beauty of the inhabitants to shine.

Drilled Aquariums

A Drilled Aquarium is an aquarium that has an overflow system in it and the tank has holes drilled in its base or rear panels to allow pipes to be run out of sight to a sump.

This type of system allows the equipment to be hidden in the sump which usually sits in the stand. This provides for more variety in equipment selection, more equipment to be used and hidden and increased water volume to allow for higher stocking levels.

Rimless Aquariums

Rimless Aquariums are a style of aquarium that has become popular in recent years due to the minimalist look they provide.

Rimless refers to the top of the aquarium being nothing but glass. There is no canopy or any trim around the top edges. All rimless aquariums are open to the room.

Rimless aquariums can be Glass Only, AIO or a Drilled Aquarium

Designer Aquariums

RedSea Max Nano

The aesthetic look of today’s aquariums can play a hugely important role in someone’s home. Today’s modern society is wanting a piece of art in their home so why should the aquarium be any different.

Featuring stylish aquariums with modern stands and light arrays can really make an aquarium a showpiece of anyone’s home.

These types of aquariums will demand the higher price tags but they are worth it!

Red Sea does a great stunning selection of Nano Aquariums that are perfect for the beginner.
You can find out more about them Here at

Are Nano Aquariums Easy Or Hard?

Nano aquariums are no different than a larger aquarium, but they do have their own nuances that you need to be aware of.

In some respects, they can be a little easier and cheaper to set up as the equipment can be cheaper, the number of consumables you use will be less and the time it takes to maintain it can be less.

Because of their size, it costs less to stock it with corals and you are very limited to the species and number of fish you can have in it.

But, even though they may cost you less, they can be just as much work as a larger aquarium and if things go wrong, the tolerance for recovery is much less due to the volume of water in a nano aquarium.

Are There Any Cautions With Nano Aquariums?

Here are a few things you need to be aware of with small nano aquariums:

  • The smaller the volume of water, the more susceptible the water is to instability due to external influences
  • They heat up and cool down faster, causing larger temperature fluctuations
  • They will evaporate water and if not looked after, the salinity can quickly skyrocket
  • Direct sunlight can quickly heat up a nano aquarium
  • Incompatible fish can fight and kill or cause illness
  • Fish that are too large will become stressed and die or cause illness
  • You have to stock less fish than you would like
  • A mistake by you could easily and quickly crash the aquarium

How Do You Ensure Water Stability In A Nano Aquarium?

The larger the aquarium, the slower changes occur because there is more water volume to dilute a problem. As mentioned above, temperature and salinity fluctuations can be very large, and happen quickly in a nano aquarium, but there are devices purposely made for a nano aquarium to help combat them:

ATO – Automatic Top-Off System

An ATO is a must on any saltwater aquarium. It is a simple device that monitors the water level in your aquarium and when water evaporates and the water level drops, the device turns on and replaces the lost water.

A Typical ATO System

With an ATO it is important to remember that the water lost to evaporation is only FRESHWATER as salt does not evaporate! As the aquarium water evaporates away, it leaves behind the salt. If no more water is added to the tank the ratio of water would get less, while the amount of salt would stay the same. Therefore, the more water that evaporates = The ‘Saltier’ your aquarium water will become.

By replacing the same amount of water that evaporated with freshwater, your aquarium salinity will always stay constant.

With a Nano aquarium, you are very limited to space and to keep your already small aquatic real estate to a maximum, you need an ATO System that is discreet.

Here are the top 3 ATO systems purposely designed for a nano aquarium. All are linked to for further information, pricing and reviews:

  1. AutoAqua Smart ATO Micro – Automatic Top Off System
  2. Tunze Osmolator Nano 3152 ATO System
  3. XP Aqua Duetto Dual Sensor Nano ATO System
Pump Head
Auto Aqua Smart ATO MicroOptical6.5ftYes$139.95
Tunze Osmolator Nano ATOFloat7.5ftYes$139.99
XP Aqua Duetto Nano ATOOptical8.2ftYes$119.99


Heaters play a key role in keeping your aquarium water in the desired 78°F-80°F temperature range. A device that is never really given much thought in the larger aquariums but in a nano aquarium, it is very important!

To enable stable temperature control in such a small aquarium you need a reliable, small, digitally controlled heater and in my mind, there is only one type that I would trust in a nano:

Cobalt Aquatics Neo-Therm

These heaters have several great selling features that are perfect for nano aquariums:

  • Can maintain set temperature to +/-0.2°F!
  • They are flat and black – Helps to make them invisible
  • Digital control for reliability
  • Run-Dry protection
  • Very reliable with a great pedigree.
  • Range of wattages to suit every aquarium size

They are a little bit more in price than most of the common heaters but they are worth the cost! Most heaters can only maintain their set temperature of +/-2°F and this is far too much of a swing for a Nano-Reef Aquarium!

Spending a little more here could save you hundreds in lost coral and fish in the future!

For More Information, Wattages, Reviews, and Prices
Click Here to find them at

Mini Chiller

A mini chiller is the exact opposite of the aquarium heater. This device prevents your aquarium from overheating. Working in conjunction with your heater it can provide rock-solid temperature control of your water.

Perfect for those locations where there is no air conditioning in your home/office or the only location to place the aquarium results in direct sunlight.

There is only one Mini Chiller I would recommend for a nano aquarium:

Chill Solutions CSXC-1 Thermoelectric Aquarium Chiller

  • Maintains set temperature to +/-0.1°F!
  • Small and discreet to be easily hidden
  • Digital temperature control
  • Simple temperature setting
  • Fully automatic
  • Suitable for tanks up to 30 Gal

This device may seem excessive to a beginner but working in conjunction with your heater the two will be able to maintain your water to within 0.2°F of your chosen setpoint. That will really help the stability of the water in your nano aquarium!

This may be a device to keep in mind and see how your first summer with your nano aquarium goes. If the tank temperature starts to get too high then this will be one of the best investments you can make for your nano aquarium.

It is easy to install, hide out of sight and if your Nano aquarium is an All-In-One type, the chiller can just connect into your existing return pump!

For More Information, Reviews, and Prices
Click Here to go to

Example Nano Reef Setups

If a nano aquarium is something you may be interested I put together a Setup Guide to help you look at the different styles of aquarium with everything you need to get you up and running with pricing:

To Finish

A Nano Aquarium can be a great aquarium to start with but you will get the bug and it will not be long before you are planning to move up to a larger aquarium. With some careful planning and nice livestock selection, you can have a beautiful showpiece that all your friends will want to see!

Further Reading

To help you further in your quest you may find these other articles of ours helpful:


Hi, I'm Richard and I have been an avid aquarist for over 30 years with a passion for Saltwater Aquariums. I love to pass on my knowledge to help others get the same amount a pleasure out of this hobby as I do. View my About Me page to find out more about me & my mixed reef aquarium.

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