Since the creation of the Nano Cube, small reef aquariums have become quite popular because they offer a convenient way to keep a reef aquarium when space, budget, and time are limited.
A nano tank is simply a small aquarium, typically anything below 40 gallons.
Why is Patience So Critical for a New Nano Tank?
Setting up a new tank is exciting.
Building, stocking, and seeing my work come to life is quite rewarding.
Rushing through the planning and setup process can lead to numerous problems.
Most importantly, my tank needs time to establish.
Once I have rock, sand, and water in the tank, I let it run for a full four to six weeks before adding fish.
Allowing the tank to run gives the bacterial foundations sufficient time to establish, ensuring new aquatic pets the best chance to survive.
Another result of impatience is making adjustments too quickly.
Stability is key to the health of an aquarium, and I have learned that changes to the environment should be made slowly.
Drastically increasing lighting, changing water flow, adjusting additives, or adding too much new livestock at once are all examples of modifications that can stress the tank’s inhabitants. In nano tanks, the effects of such changes are magnified even more drastically.
The resulting stress can be misleading.
It may appear that a new lighting schedule or flow pattern is too strong, when in fact the corals or fish are simply stressed because of the drastic change and were not given the proper time to adjust to more optimal conditions.
How Do I Choose the Right Fish and Corals?
Small aquariums cannot support large populations of fish, and it is critical to choose the appropriate type of fish that will thrive in such a confined space.
The key is research. Before heading to a fish store, I have a solid idea of which species I am looking for.
My choices might be restricted by what my local fish store has in stock, but I do not let that scarcity limit my options.
Many fish stores will take special requests, or I may consider purchasing from one of the various reputable online retailers.
Waiting for the right fish is well worth the effort.
I never purchase a fish or coral I have never heard of, as doing so almost always leads to problems.
I make sure to have a solid understanding of what the animal needs to thrive in captivity.
It is important not to purchase a juvenile fish that will quickly outgrow the tank.
While a baby blue tang may appear to be the perfect size, in reality, they grow quite large and require a great deal of space to swim.
A tang in a small nano aquarium will only cause stress, which leads to aggression and an increased risk of infection and disease.
I like to make a list of my top five fish, ensuring that they are all compatible, and then I head out to a fish store.
I have found that I cannot always find what I am looking for, but my patience and commitment to the plan ultimately lead to success.
What About Choosing Corals?
I also take smart coral selection seriously.
I make sure to understand what a particular coral needs.
I ask myself: Is it aggressive, and will it potentially kill other corals?
Will it be prolific and out-compete everything else?
Are my water parameters stable enough to keep the corals happy and growing?
Are conditions optimal in terms of lighting and flow?
Knowing the answers to these questions gives me an advantage and ensures new corals will assimilate nicely into the small reef.
How Should I Feed a Nano Reef Tank?
I find feeding my fish and corals fun, but I am careful not to get carried away.
Too much food will foul the aquarium’s water, especially in a small tank where there is not a substantial water volume to dilute the resulting waste.
I always turn off my filtration system when feeding.
I also rinse my frozen foods using reverse osmosis deionized water and strain out the usable food particles.
I take advantage of feeding stations to corral the fish food and keep it away from my filtration system.
Algae clips and grazers are also excellent tools to reduce food waste.
My fish will quickly consume the food I give them in under two minutes.
I sometimes feed in stages to help distribute the food to various tank inhabitants.
Coral foods should be used sparingly in a nano tank, if at all.
In my experience, leftover fish food can easily feed the corals.
Prepared coral foods are typically very small in particle size and designed to stay suspended in the water column.
A significant portion of prepared coral food will go uncollected, increasing waste levels.
I always target-feed corals using a bulb syringe. I also make it a regular practice to maintain my mechanical filtration to remove the filtered food particles.
Why is Using the Right Water Source Essential?
I avoid using de-chlorinated tap water at all costs.
I recommend getting a personal reverse osmosis deionized system or purchasing filtered water from a local aquarium shop.
A reverse osmosis deionized system filters tap water to be clean and free of contaminants that could be toxic to fish and corals.
It will also remove impurities that contribute to nuisance algae growth.
What is the Correct Water Change Schedule?
Small tanks require a strict water change schedule.
A water change on a small tank is the best way I know to keep it stable.
With most of my nano tanks, I perform a 20% water change every 7 to 10 days, especially when keeping a nano reef with corals.
Doing so replenishes the necessary elements that corals need and also dilutes waste levels.
Creating a regimen and sticking to it is the best approach.
With a frequent water exchange, the tank will not get to a point where water quality diminishes so severely that the animals suffer.
Having a reverse osmosis deionized system at home makes the process easier because I will have fresh, clean water on demand for mixing saltwater and filling my top-off container.
I can also make my own saltwater at home if something goes wrong or my local fish store is not open.
Filtration systems on smaller, all-in-one aquariums are minimal and do not allow space for advanced equipment.
With a frequent water exchange schedule, I can effectively eliminate the need for a bulky protein skimmer, media reactors, and other filtration equipment found on larger reef tanks.
Are Nano Protein Skimmers Worth It?
In my experience, tiny protein skimmers are classically problematic.
For a skimmer to fit into a nano aquarium’s filtration compartment, it will need to be very small.
The small size means it will have a tiny reaction chamber, which poses a fundamental problem, as a skimmer requires a large reaction chamber to properly remove waste and perform without frequent adjustments to air and water.
There are a handful of nano skimmers that work better than others, but they generally will not pull out waste as one might expect.
Small skimmers provide the benefit of gas exchange and removing some waste, but it is important to understand that some of the best nano tanks operate without a skimmer.
I do not worry if I have trouble finding one that fits my tank.
Instead, I focus on maintenance and adhere to a frequent water exchange schedule to remove and dilute organic waste.
How Often Should I Perform Filter Maintenance?
Filter maintenance is crucial with a nano tank because conditions can go downhill fast.
A delay of a few days can lead to nutrient level spikes.
In my experience, mechanical filtration like filter pads and socks needs to be cleaned or replaced every 3 to 5 days.
If a tank is very clean, I might go a few days longer, but I remember that when trapped waste is left to break down, bacteria will create nitrates.
The same rule applies to chemical filtration media like carbon and absorbent resins.
I replace such media as soon as it becomes exhausted to prevent leeching or additional waste buildup.
Some media lasts longer than others, so testing the water is important for understanding when it is time for a replacement.
I like to follow the rule of ‘when in doubt, just change it out.’
Keeping a healthy stock of replacement filter media on hand ensures I am never stuck without a new bag of carbon or a clean filter pad.
Why is an Automatic Top-Off System Necessary?
Using an automatic top-off system will save a ton of headaches.
Manually adding freshwater to replace evaporation loss is tedious and causes swings in salinity levels, which will stress the tank’s inhabitants.
In small aquariums, evaporation occurs at the same rate as in a larger aquarium, but the resulting rise in salinity is far more drastic.
An automatic top-off system tops off the aquarium with freshwater and keeps the tank’s salinity stable.
There are quite a few options for small automatic top-off systems with tiny sensors that fit nicely into nano tanks.
The Tunze Nano, the XP Aqua, and the Micro ATO are all excellent choices.
How Important is Regular Water Testing?
With a small aquarium, I find it important to keep a close eye on water parameters, especially when keeping corals.
A regular testing regimen gives me an idea of what my corals are consuming, indicates whether my filtration and maintenance schedules are sufficient, and gives me peace of mind that my tank’s inhabitants are in an optimal environment.
Keeping a log for reference and having a full set of quality test kits is critical for me.
The log helps to reference past tests, and having the test kits at home makes neglect more difficult.
When first starting out, I suggest seeing if local fish stores offer a water testing service or considering a mail-in water test kit.
I believe a successful reef hobbyist is a keeper of water chemistry.
Using test kits to identify trends and understand how the water changes over time has given me a much better understanding of the most complicated aspect of the hobby: the water itself.
What Basic Parameters are Often Forgotten?
I find it is easy to get so caught up in maintenance and scrutinizing every available element for the corals that I forget the basic parameters that keep a tank thriving.
Change happens fast inside a nano tank, a fact that remains true for temperature, pH, and salinity, all of which are very easy to monitor and should not be forgotten.
An accurate thermometer, a reliable refractometer, and a quality pH test kit or monitor will make the process easier.
Aquarium controllers like the Neptune Systems Apex and the GHL ProfiLux offer an excellent solution for real-time monitoring and control of these parameters.
An expensive controller may not seem worth the expense for a small tank, but in my view, they are just as useful, if not more so, compared to a large system.
The animals inside a nano tank require the same attention and care as those found in large reef tanks.
What Does It Take to Be a Successful Nano Reefer?
I have learned that no matter the size of the tank, success takes work.
The more work I put into it, the more I get out of it. Keeping a small reef tank takes just as much commitment as a larger tank; the only difference is the cost of equipment.
Keeping a reef tank is a journey, and all the while, I am constantly learning.
No matter how much research I do, I can never predict when a fish might jump, become ill, or when a critical piece of equipment might fail. Such events happen and can be disheartening.
What I can do is be prepared.
I keep extra heaters and pumps on hand, utilize battery backups or buy a generator, use a screen top, source livestock from a reputable distributor, and mentally prepare myself for these situations, as they will inevitably happen.
I do not let such events discourage my passion for reef tanks. I keep working and keep learning.
Every hobbyist goes through it and will experience some level of disappointment.
I ask myself what keeps my passion for reef tanks alive, and then I nurture those desires. By doing so, I accomplish my own personal level of success.
Conclusion
To avoid common nano reef tank mistakes, I always start by patiently cycling my tank for at least 4 to 6 weeks before adding any livestock.
The wait gives the biological foundation time to establish properly.
I carefully research and choose small, compatible fish and corals that can thrive in a limited space.
When feeding, I stay conservative and target-feed corals to reduce waste.
I only use purified reverse osmosis deionized water to maintain clean and stable water quality.
I perform 20% water changes every 7 to 10 days to replenish essential elements and dilute harmful buildup.
I clean mechanical and chemical filter media every 3 to 5 days to prevent nutrient spikes.
To keep salinity consistent, I use an automatic top-off system.
I also test essential water parameters regularly, including temperature, salinity, and pH, to ensure everything remains within safe and healthy ranges.
My name is Chibuzor Abraham Mba, and I’m the aquarist behind this website. I’ve spent years exploring the fascinating world of aquariums—especially small-scale tanks like nano and pico setups. Over time, I’ve made my fair share of mistakes, and through each one, I’ve learned valuable lessons.