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How to Set Up a Nano Reef Tank

After 50 plus years of fishkeeping, I finally decided to set up a nano-reef tank last week.

Learn everything you need to know about nano reef tank setup, from achieving proper pH and specific gravity to performing water changes and dealing with red slime algae.

Learn everything you need to know about nano reef tank setup, from achieving proper pH and specific gravity to performing water changes and dealing with red slime algae.

Nano Reef Tank Setup

Fishkeeping has changed in the last 50 years. I still remember that metal-framed glass guppy tank that my brother and I accidentally smashed during horseplay. About 30 years ago, I set up my first saltwater fish tank decorated with coral rock and gravel. A few inverts such as anemones and crabs were included, although they didn't do as well as the clownfish that lived for 6 years.

These days saltwater fishkeeping is a whole new art thanks to more information on the nitrogen cycle, flow rates, additives, and lighting needs, especially for sedentary invertebrates like sea anemones and soft corals. A few years ago, it was suggested that saltwater tanks include at least 20–30 gallons of water, but with more knowledge concerning reef maintenance and greater expense in reef setup and upkeep, articles and publications have been coming out on how to maintain nano reefs; that is, reef tanks of 10–20 gallons or less.

In this article, I will walk you through the basics of nano reef tank setup and maintenance. Here is what you will learn:

  1. Beginning steps for setting up a nano reef
  2. Adding bigger creatures
  3. Performing a first water change in a new aquarium setup
  4. Checking the tank over the course of a week
  5. Achieving the proper pH and specific gravity
  6. Adding more sessile invertebrates
  7. How to deal with red slime algae
  8. How to remove bubble algae

I also provide a series of updates on the condition of my tank and its inhabitants over the course of 9 months. Finally, you will find a video covering 6 important tips for brand new nano reef tank owners.

An 8-gallon nano-reef tank containing saltwater and live sand.

An 8-gallon nano-reef tank containing saltwater and live sand.

1. Beginning Steps for Setting Up a Nano Reef

My first step last Friday was to purchase an 8-gallon Aqueon Evolve plastic tank with an included LED light and hidden filter. I also purchased salt mix for 10 gallons (Instant Ocean, the same brand I used 30 years ago for a fish-only tank) and some CaribSea Arag-alive live sand with small enough grains to allow creatures to easily burrow.

The proper amount of the salt was placed in the tank with enough distilled water to bring the water level within about 1 inch off the top (in an estimated 1 cup salt per 2.2 gallons of water). A sealed plastic bag of distilled water was also placed in the tank to displace enough water to leave space for later insertion of the live sand and rock. The filter was then run to mix the salt. This took about a day. Then the sand was added, which clouded the water considerably and released a few small swimming crustaceans about the size of daphnia.

A day or so later, I added some live rock and rock rubble in a pile to provide cover for later creatures and to help seed the tank with beneficial bacteria. This rubble contained a few tiny filter feeders which opened their tentacles that evening. Parts were also covered with red coralline algae. The pile, which consisted of 2 baseball-sized pieces of rock, plus rubble, was about 4.5 inches tall by 5 inches in diameter. The tank was maintained at room temperature in my fish room (75–80 degrees Fahrenheit).

2. Adding Bigger Creatures

Five days after the addition of the live rock, I checked various water parameters and took a sample to the fish store to have it checked. Our results agreed. Nitrite and ammonia close to zero, nitrate less than 5 ppm, s.g. 1.0235, and pH 7.8. The last measurement seemed kind of low, possibly due to the live sand, but we decided to add some critters anyway.

I picked out 2 blue-legged hermit crabs and 2 redhead gobies, the latter possibly a pair, based on differences in size. The crabs and gobies were separately bagged, and when I got them home, I acclimated them by floating the bags in the tank and adding some tank water to the bags, bit by bit, over half an hour. I initially removed some of the bag water to allow more space for tank water.

After 4 or 5 tank water additions, the bags were upended into the tank. Note that I only waited 5 days for creature addition, hoping that the live sand and rock had sufficient bacteria to process any nitrogenous wastes.

One of the red head gobies, outlined in red.  Extra shells for the hermits at lower left.

One of the red head gobies, outlined in red. Extra shells for the hermits at lower left.

3. Performing a First Water Change in a New Aquarium Setup

By now, I have had several days to watch the two gobies and two hermits. The hermits are active day and night, but more so at night. The gobies are constantly active by day and have the coolest way of turning their heads from side to side. There is a little chasing but no real conflict between the gobies.

Today I noticed that one of the hermits has traded his/her smooth dark shell (possibly a Cerith shell) for a white knobby shell that I didn't even know was in the tank (must have been hidden in live rock or rubble- maybe a vase shell [Vasum]). Also, I siphoned out 1 gallon of water into a gallon distilled water jug and poured in some premixed water (marine salt + RO water from the fish store) from a 2.5 gallon distilled water jug.

Actually, I measured the new water by using it to fill an empty gallon jug first. So far, I have avoided having to get a 5-gallon bucket, the 2.5-gallon jug being the largest I have. I've also been daily feeding the fish and crabs. Food has included cyclopeeze, decapsulated brine shrimp eggs, and chopped frozen Mysis shrimp. The gobies go after all 3, and hopefully, the crabs are scavenging leftovers, although I have been careful to minimize the amount of food added. I have also turned off the filter for a few minutes to allow the food to be eaten before it is pulled into the filter.

I guess in a few days, or so I can recheck water parameters and make sure that they are staying stable.

4. Checking the Tank Over the Course of a Week

I noticed what looked like a dead hermit crab today (4/3), but it was only a shed carapace. Both hermits are still moving around. I also tried gobies on sinking cichlid pellets (medium size). They grabbed them but spat them out (too large and hard). Hopefully, they will eat them later!

On 4/5, I dropped by the fish store to get extra filter inserts for the Aqueon tank. I also checked on possibly getting some zoanthids to add to the nano. pH is still about 7.6, and they suggested I bring in a water sample on 4/7 to see if I need to add a buffer. I also suggest the addition of African Rift Lake salts to help buffer the tank. I added 1/8 teaspoon, checked a few hours later, and added another 1/8. I checked Saturday, and there was no great pH increase, so I added another 1/4 teaspoon. of Rift lake salts.

I do have some liquid rift lake buffer, but they said not to use that yet. I also have discovered a sea anemone-type creature with a tentacle spread of about 1/4 inch at the base of one rock, and the second hermit crab has shed. Hopefully, tomorrow (4/7), I can get some buffering done, have a photo of the anemone checked to make sure it isn't the dread Aiptasia glass anemone, and maybe add a zoanthid if the water is OK.

Note the red outlined anemone (soft coral?)

Note the red outlined anemone (soft coral?)

5. Achieving the Proper pH and Specific Gravity

Dropped by the local fish store today and found that pH is okay (8.2, my pH strips are not correct), but specific gravity is around 1.020 and I am shooting for 1.024-5. They suggested water changes until I reach that specific gravity level. I corrected the new water to 1.027 and then added 1 gallon to the tank. Tank is still around 1.020. I will need some additional water changes, so I mixed up 2 more gallons with RO water and will check it tomorrow. The anemone I saw was ID'd as a clove polyp. They can spread, but not as badly as Aiptasia. It is a type of soft coral related to pulsating Xenia.

6. Adding More Sessile Invertebrates

After getting the pH and specific gravity right where I wanted them and having ammonia and nitrite check out as 0, I was able to add a couple of sessile invertebrates. These consisted of a zoanthid or colonial anemone colony containing green and brown tentacled polyps with orange to red centers and a reddish-purple encrusted piece of a coral skeleton that eventually bloomed (it took a couple of days) into green star polyps, with ghostly greenish tentacles containing photosynthetic zooxanthellae.

All did okay for a week and then I felt able to add some cylindrical stemmed caulerpa algae (said to be relatively slow-growing) and a single red mushroom polyp. The former went into a back corner of the tank and then I tried dropping the latter into a crevice in the rocks, but it soon contracted and sank out of sight, so I placed it on the sand against a dead coral branch. Another few days saw the appearance of some red and some green bubble algae, forms that can overgrow a tank.

Red bubble algae in photo center grows on live rock. Goby in upper left for size comparison.

Red bubble algae in photo center grows on live rock. Goby in upper left for size comparison.

7. How to Deal With Red Slime Algae

In addition to getting red bubble algae, the dreaded red slime algae also appeared on rocks and sand. Each day I scraped it off and it was back the next day, threatening my button polyps (zoanthids). Finally, I tried some erythromycin provided by my local fish store (this alga is actually a bacterium). Within 2 days the red slime was gone. However, my zoanthid colony had closed up and would not open. I attempted to move it to a higher spot in the tank and 2 or 3 days later, 3 or 4 polyps of the approx. 20 opened.

A check of the online info turned up a bunch of possible problems with these button polyps. Apparently, they are sturdy in the long term but sensitive in the short term to aluminum, handling, fish nibbling, parasitic snails and sea slugs, and changes in water parameters. In one case, an aquarist got his polyps to open just by changing the specific gravity by .001 unit. In other cases, they seem to have been closed for weeks or months and then opened up and reached good condition again.

To confuse the matter further, I had added a Poly-Filter pad to the tank a couple of days after the medication. I've just decided to avoid any changes to the tank for a while and see if the polyps come around. They already (May 3) are partly open (about half of them for part of the day). Maybe they just need to adapt!

My mushroom polyp, by the way, has not divided yet but opens up quite well. There are now 5 clove polyps connected to each other by runners (stolons) and the star polyps are doing well. A strange little (2-3 milimeters high) transparent vase-shaped object has appeared on the rocks with a couple of filaments sprouting from the top. It might be a small tunicate. A tuft of filamentous red algae the diameter of a dime is also growing daily.

8. How to Remove Bubble Algae

I found an online instructions on how to remove extra bubble algae with a scalpel and rigid siphon tube to avoid the spread of spores from broken bubbles. Tried this a little, but the red bubbles are not really a problem yet.

I'll try to get a picture of the partially open zoanthids.

Two open zoanthid colonies to right

Two open zoanthid colonies to right

An Update on the Condition of My Nano Reef

Thanks to all for your comments. FYI, I checked pH, nitrate, nitrite, alkalinity, specific gravity, and ammonia before adding any creatures. The live rock was from a local shop that has a large recirculating system. My understanding was that live rock/live sand could speed up the maturation process. Also had the shop check the above parameters before additions. The chemicals in picture 1 are a box of Instant Ocean to the right and a bottle of dawn detergent to the left, which is actually on the back of a sink separate from the tank "stand."

To update you on the survival of original critters, one original zoanthid colony is doing well, the mushroom polyps are doing well, and both gobies, the Astrea snail, and both octocoral polyps are doing well. Clove polyps have spread to 10 polyps. The other original zoanthid only has about 1 out of 6 or 8 polyps open, but I treated this one with nitrofurazone (possible "zoa pox"?) per some online advice and all still look alive, just not yet opening.

I have also added 2 larger pieces of live rock (by the way, I understood earlier pieces were cured), a few more mushrooms, another 2 zoanthid small colonies, and a Kenya tree coral. Parameters all still look okay, with ammonia 0, nitrite 0, and nitrate about 10 ppm. The filter insert does have carbon in it and I am using Poly-Filter material also, along with live rock rubble in the filter.

My big concern now is that a new piece of rock has several small clams as an integral part of the rock. I could break off the outer valve and kill/clean out the creatures or just leave it as is and hope that they do okay. I am feeding commercial phytoplankton every few days.

I appreciate all the input. This is a learning experience for me and hopefully also for you. I have been depending on the advice of the local shop (have been a customer for 50+ years) and a number of books including:

  • The Nano-Reef Handbook by Brightwell
  • Mini-Aquariums by Jay Hemdal
  • Corals by Tullock
  • a couple of other coral books from the library.

Hopefully, I haven't added creatures too quickly. Everything I read says that zoanthids are easy to keep, but of the 4 colonies I have, only 2 have been trouble-free. I have tried to stay with the ones that appear to be Zoanthus sp. since I understood the other genera tend to secrete palytoxin.

After adding a couple more pieces of rock.  These look uncured to me.  Note the thin opening of one clam (black crescent) within the blue outline.

After adding a couple more pieces of rock. These look uncured to me. Note the thin opening of one clam (black crescent) within the blue outline.

When to Add Livestock to a Nano Reef

Other than just waiting for a standard time, as long as water parameters are okay, what would be the best way to know when to begin adding livestock to a nano reef? I guess I added stuff so early because I heard that live rock was an effective biofilter and was told that the use of the live rock and sand with already established bacteria would naturally shorten the start-up time.

Where are the fish?

Where are the fish?

Understanding Chemistry and Biology

I am retired, so have a lot of time to check water parameters. Also, I have a biology degree and worked for 5 years in industrial chemistry. Obviously, the biology and chemistry experience aren't necessary, anyone can use a test kit, but it may help me a little. However, over the years I have run into a lot of folks who were more successful than I was at keeping and breeding freshwater fish who worked at a wide variety of jobs. Just don't want to make the setup look too easy.

The Condition of My Nano Reef After 3 Months

Three months after beginning the setup, I feel like I have learned a lot, but still have far to go. Mostly I need to be patient and let things develop in the tank (less of a control freak). Button polyps are reproducing in a couple of spots, mushrooms are doing a bit better (I reduced light from 14 hours per day to 11 based on a suggestion from my local fish store to get mushrooms to open more), gobies and Astrea snail are still okay, and I currently have 3 blue legged hermits and a few more spare empty shells.

Recently a couple of gastropods (snails) have shown up. Both appear at night. One looks spiny, but that is only his exposed mantle. I am betting it is some type of cowry, the shell once used as money by Pacific islanders. The other has a rather flat mahogany-colored shell and a relatively large body "busting" out of the shell. Each of these is only about 3/8 inch long. A gammarus or "scud" type crustacean is also appearing occasionally day or night. Here is a pic of the tank with some of the life labeled. I will ID the labels next.

Labeled view of the tank

Labeled view of the tank

A Key to the Above Picture

Here are the animal names for the various labels above:

  1. Kenya tree coral
  2. Button polyps
  3. Button polyps
  4. Hermit crab
  5. Button polyps
  6. Mushroom polyp
  7. Star polyps
  8. Mushroom polyp
  9. Mushroom polyp
  10. Clove type polyps
  11. Button polyps
  12. Clam (oyster?)
  13. Oyster
  14. Oyster
  15. Codium intricatum algae (dead man's fingers)
  16. Spirorbic worms
  17. Button polyps

Not shown: astrea snail, asterina starfish, red face gobies (2), 2 more blue legged hermits, unknown sp. bristleworms.

The Condition of My Nano Reef After 4 Months

At this point, red slime algae is not at all visible. I have 3 small shelled snails called Stomatella snails, two with a brown shell and one with a red shell. They appear to be algae eaters. I have also acquired a couple of detritus eating tiny serpent stars with a total arm spread about as big as my small fingernail.

At a relatively new local saltwater store, I found several colors of Ricordia, a mushroom polyp with tentacles covering the disk. These are said to survive photosynthetically, but also will take small food items, like small Mysis shrimp. I purchased two of these, one red and one yellow. Upon putting them into my tank, the yellow one became iridescent green and the red one became blue.

These colors do not appear to be a difference in lighting, they remain under different colored light. I don't know whether light quality or quantity or even water quality is responsible for the color change. They seem to be doing okay, except they are attached only to small pieces of gravel, and the current in the tank was pushing one into the other which moved them both toward a pink mushroom polyp and caused it to contract. I solved this problem by putting the first Ricordia into a seashell so it wouldn't be moved by the current.

I have also noticed a tiny gastropod that looks like a chiton. The color is a kind of red plaid. The largest bristleworm I have seen is about 2 inches long, with several in the tank. A close look at the front glass also reveals some tiny pods about the size of a daphnia. All these tiny inverts seem to be more obvious/active at night when a flashlight is used to illuminate the tank, but occasionally one is visible during the day.

The accompanying photo shows the tank as it is now, with the Ricordia at the lower right front.

The Condition of My Nano Reef After 9 Months

I have now reached the point where water quality and the water change schedule are pretty stable. The current puzzle is where and how to place additional invertebrates so they don't negatively affect one another. I've moved the Kenya tree coral to the rear left which seems to have wiped out the green zoanthids in that area. I also added a mushroom leather coral as a possible hideout for an orange and white anemone shrimp (Periclimenes).

Unfortunately, the shrimp was killed after a couple of days by my red-headed gobies, one of which has taken up residence in an empty snail shell. I also saw one of the gobies kill a blue-legged hermit crab that was out of its shell and trying to steal the shell of another. Several Ricordia and Rhodactis hairy mushroom polyps have been added and they seem to be the hardiest things I have.

Some of my zoanthids are also having trouble with debris settling among them followed by algal growth. I have added a small (150–200 gallons per hour) Rio+ 600 pump in the tank to increase current and keep the zoanthids clean. Also added a branched candy or trumpet coral (Caulastrea) which I accidentally split when operating in the tank. I used scissors to complete the split and placed the smaller frag elsewhere in the rockwork.

Several zoanthid colonies have been attached to the live rock with superglue gel (Loctite brand) or epoxy made by Instant Ocean. The former tends to dry white in seawater and is somewhat effective with gluing items to a flat surface. The epoxy works best to fill in around a frag that is placed in a hole or cavity. The pic below is a Palythoa type zoanthid that I tried to add, but it caused me to have an allergic reaction, so I returned it to the shop.

The large brown zoanthids I reacted to.

The large brown zoanthids I reacted to.

Here is the tank as it was before adding the new pump, with candy coral in upper right and mushroom leather coral in upper left.

Tank with candy coral at upper right and mushroom leather at upper left.

Tank with candy coral at upper right and mushroom leather at upper left.

Necessary Maintenance Tools

Here is a photo of most of the tools I use to weed and groom the nano-reef. That's a lot of stuff for an 8-gallon tank! Below is the key to the items and what they are used for:

  1. Angled scissors for trimming algae.
  2. Slotted spoon for picking up large items.
  3. Angled forceps for grabbing items in the shadow of a rock.
  4. Planting tool for pushing stuff into gravel (plastic scraper not used on acrylic).
  5. Disposable pipettes for dropping food on corals.
  6. Long extendable pipette, same use.
  7. Grilling grabbers for picking up large stuff.
  8. Algae sponge for an acrylic tank (some are glass only).
  9. Baster for introducing food.
  10. Paintbrush for algae removal.
  11. Chopsticks for stirring gravel and algae removal in tight spots.
  12. Adjustable cutter/grabber designed for aquarium plant use.
  13. Large reptile feeding forceps, probably the most useful tool for grabbing, nudging into place, etc.

I have also used other size paint brushes depending on the algae removal site, as well as tried several tweezer-type forceps, but the latter tend to rust, even if rinsed and dried. A variety of tools is needed because I am required to work around a lot of invertebrates and live rock in the tank without knocking any over or damaging them.


This content is accurate and true to the best of the author’s knowledge and is not meant to substitute for formal and individualized advice from a qualified professional.

© 2013 animallife


animallife on November 22, 2015:

Sounds great! I have tried several other things since last post. I have kept a possum wrasse for awhile, a frogspawn coral, and am now trying a Lobophyllia coral. A chalice lasted many months, but eventually regressed when I got lazy with water changes. Will try to continue story with photos when I get a chance (grand kids and a PT job have intervened).

Mike on August 19, 2015:

I have a 30 gal bio-cube saltwater tank and only waiting a few days to add fish is a gamble as the tank will have a few high spikes of nitrate cycles within the first few weeks to few months as well as dips in the ph dew to everything leveling out but as far as it taking a lot of effort to maintain a saltwater tank i have put almost no effort into my tank and have bred a pair of clown fish and have lots of corals and emerald crabs and hermit crabs, zooanthids as well as a kenya tree i have fragged many times you dont need to be a chemist to keep a tank healthy ! Its a great past time for kids and it is informitave

Abdus Salam from Bangladesh on May 31, 2013:

Congratulations!! your hub on hub of the day. Very informative hub. Thanks for sharing....

Md.Sariful Islam from Bangladesh on May 31, 2013:

Great job. I knew absolutely nothing about this subject but thanks to your insight I've learned so much. Voted up and Awesome .

Marla J Neogra from Parkersburg, West Virginia on May 31, 2013:

Cool for you, way too involved for me. I have a hard enough time keeping up with a cat and dog! I voted Interesting, Useful and Up.

rose-the planner from Toronto, Ontario-Canada on May 31, 2013:

This is truly interesting! I have always been fascinated by awesome tanks with colourful and unusual creatures gracefully moving about. There is a large aquarium store near us which we go to often for fun. I have always wanted a beautiful aquarium but clearly it takes a great deal of dedication like you have demonstrated so well. Thanks for sharing! Take care. (Voted up) -Rose

Melissa A Smith from New York on May 31, 2013:

From what I can see you added fish and inverts too early. Maybe your live rock was 'cured', but with nano-reefs, it pays HEAVILY to wait things out. One little mistake will lead to future devastation with such a small tank size. I would recommended anyone starting these to wait at least a month before adding any livestock. The longer, the better, especially for fish. This is why larger aquariums are easier.

Natasha from Hawaii on May 31, 2013:

You have a very cool tank! My guy kind of wants a salt water tank, but I'm afraid of how much work we might have to put into it! They really are beautiful, though, so maybe I'll hazard it one day.

Lucy Jones from Scandinavia on May 31, 2013:

Brilliant hub and so interesting. I knew absolutely nothing about this subject but thanks to your insight I've learned so much. Voted up and shared. Thanks for sharing.

Subhas from New Delhi, India on May 31, 2013:

Hi animallife! You have produced something like a new and fresh idea which we all are dearth of. Nice elaboration.

Gous Ahmed from Muslim Nation on May 31, 2013:

Very interesting article. I don't particularly like looking after fish, takes too much effort on my part. The kids love staring into fish tanks though.

Maybe when they grow up and take more responsibility we may buy one.

Susan Britton from Ontario, Canada on May 31, 2013:

Great job. My salt water tanks always went cloudy. Now I know why. Thank you for this information animallife.

SAM ELDER from Home on May 31, 2013:

It is really strange to see that 50+ years experienced hobbyist who adding non cured live rocks, live fishes and live hermit crabs into 5 days old tank.

It's not surprising, you have red bubble algae in your tank.

When buying fishes for aquarium we need to consider the final size of fish and the amount of water that aquarium/tank holds.

In your first picture I see chemicals near your tank.... A small drop will kill your project.

portables on May 31, 2013:

I'd always been told that saltwater fish were too hard to keep at home - it would appear that I'm wrong!

Comfort Babatola from Bonaire, GA, USA on May 31, 2013:

Good job here animallife. I love the live rock and algae idea. Might try to set one of this up since the kids can't get a dog (hubby allergic to dogs), maybe we could get an aquarium/Nano tank. The fish - If I could just remember to feed them.

Voted up and useful. And congrats on the HOTD award.

Steve Dines from Gravenhurst, ON. on May 31, 2013:

I have a 30 gallon tropical tank and a small pond with goldfish ..... after reading this hub I'm tempted to get a saltwater tank set up .... perhaps this winter.

Amy from Texas on April 30, 2013:

Good job. I would like to be dedicated enough to have this nice of a tank.