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What Is An Aquarium Refugium?

by Brian Dunleavy
What Is An Aquarium Refugium?

If you are a passionate aquarist, most likely you have come across the term “aquarium refugium.” But what exactly does it mean?

Put simply, an aquarium refugium is a separate area within your tank system that acts as a sanctuary for specific organisms and has numerous benefits for them as well as for the overall balance of your tank ecosystem.


What Is An Aquarium Refugium?

An aquarium with special compartments that simulate natural marine habitats is called an aquarium with many chambers. It acts as a retreat or shelter where certain organisms can live safely. 

The overflow systems or pipes usually connect the main tank to this refuge through which water and nutrients are exchanged. This could contain microorganisms, algae, invertebrates, small fishes and many more.

The Benefits Of Having An Aquarium Refugium

First and foremost, an aquarium refugium acts like a biofiltration unit hence its role in maintaining good water quality together with the general healthiness of the tank. The presence of these organisms breaks down waste matter into nitrates, and phosphates hence reducing chances for water pollution thus preventing algal bloom formation. As such, it gives stability to create homeostasis that enables aquatic pets to thrive there.

Additionally, some species might be susceptible to predation or aggression particularly in case they are kept in the main tanks’ but these can survive if they get transferred here hence breeding as well as juvenile hiding places. Also, inhabitants of the main tanks will feed upon living creatures belonging to this space turning it into food provisions naturally; this way all inhabitants contribute together to maintaining well-being throughout the entire tank.


Types Of Aquarium Refugiums

Various types of filtration systems exist catering for diverse needs and desires common among aquarists who have different tastes in their hobbies. 

The reef refugium is one of the commonly used kinds. It is purposely created to promote coral reef growth. Mostly, it has live rock and live sand as well as different species of macroalgae to function in natural environments for the coral larvae and other life on reefs.

Another type of refugium is a fish refugium that focuses mainly on providing shelter for small fish species. These types of refugium are often fitted with dense vegetation or places where the small fish can hide from their larger more aggressive tank mates. Fish refuges also serve as breeding areas since they offer a safe area for spawning and raising fry.


Aquarium Refugium Setup

It is essential to plan and think through the process of establishing an aquarium refugium. The first thing you should do is determine the size of your refugium in line with what your fish tank currently needs. We recommend allocating about 10-20 % of the total volume of the tank for the refugium. Then, it will be necessary to select suitable tools such as a refugium tank, lighting system, and water circulation pump. These items are vital for creating a friendly environment that would enable organisms inside to thrive.

Now you can start setting up the refugium after acquiring all the necessary equipment. Place live sand at the bottom of the refugium tank then add live rock and macroalgae. Live rock acts as a natural habitat that also provides surface area for beneficial bacteria colonization while macroalgae ensures nutrient regulation and sheltering different kinds of organisms.

Lastly, link this unit to another compartment using appropriate plumbing methods ensuring flow through moving water between these two sections.


Keeping an Aquarium Refugium

Regular maintenance is very important for your aquarium’s life support system, which includes the refugium. One aspect concerning maintenance is monitoring water parameters within the refuge area. This includes checking temperature, salinity, pH levels and nutrients present in there too. In case optimal conditions for organisms living inside have not been met, regular changing of water alongside supplemental nutrients may be needed.

Similarly, correct lighting is mandatory if the growth of macroalgae among other photosynthetic creatures within it will be realized too. Ensure that you give them adequate spectrum as well as intensity so that they thrive best in their environment. It is recommended however that from time to time one should trim or cut back any overgrown seaweed plants.

Finally, remember to examine and properly clean equipment installed in your refuge such as pumps used to circulate water and the plumbing system. As time goes by, waste materials including algae can settle on them making the whole system unproductive. You must thus ensure that this equipment is well maintained and cleaned to avoid any issues with your refuge.


Top 5 Species For Aquarium Refugiums

There are numerous choices to consider when it comes to selecting inhabitants for an aquarium refugium. Some of the popular species found in a refugium include copepods, amphipods, and mysis shrimp. These small crustaceans serve as a great source of live food for fish in your tank while helping you control algae growth there. Additionally, some macroalgae like Chaetomorpha and Caulerpa are commonly used in a refugium since they can absorb excessive nutrients and provide shelter for small organisms.

Reef refugiums are often preferred as you can also introduce coral larvae or frags so that a vibrant coral reef grows. This type of refugium is a very interesting and visually attractive addition to your aquarium setup. 


Diy Aquarium Refugium Projects

For those who have a DIY spirit and enjoy getting their hands dirty, making your own aquarium refugium can be a rewarding experience. There are countless resources available online with step-by-step instructions and design ideas for building your own refugium. Whether you choose to recycle an old tank or make one from scratch, the options are limitless.

When starting a DIY refugium project, it is important to design it carefully so that it caters to the specific requirements of your fish tank inhabitants. Take into consideration things like size, lighting and water flow to create a perfect environment for organisms within the refugium. Do not hesitate to get inventive and try out different materials and designs that will make your refuge unique.

If you are not so ‘DIY-savvy’, then do not fear the Reefco team is here! At Reefco Aquariums we are experts in designing and installing aquariums and are always happy to make your dream refugium come true. 


Common Challenges & How To Overcome Them

Just like any other component of an aquatic system, there may be problems affecting the working of the refugium. One particular problem is excessive algal growth in the refuge.

Though some algae are good and necessary for this ecosystem, overpopulation leads to an imbalance of nutrient levels which can hinder the growth of other organisms. You may want to adjust lighting duration and intensity or reduce nutrient load in the main tank or if you want herbivorous animals eating algae you can introduce them.

Another area where you can have issues is poor water flow within the refuge tanks. If water circulation becomes stagnant zones may occur, resulting in debris accumulation which negatively affects the health of species. To prevent this, make sure that your water circulation pump has been sized appropriately and placed well enough to release enough flow throughout all segments of refuge tanks. Additionally, regular cleaning the pump and routine maintenance of the plumbing system should also help maintain optimal water flow.


An aquarium refugium is a truly hidden gem within the world of aquariums. They offer a multitude of benefits ranging from natural filtration to providing safe havens for endangered species and juvenile fish. 

If you are unsure where to start, contact the Reefco team today!

by Brian Dunleavy