Want to set up your very own home reef, but don’t have space for a massive tank? Good news: you don’t need one! Nano reefs are more popular than ever, and so are the small saltwater fish that can live in them.
The best fish for a nano reef isn’t just tiny, but also friendly and not too active. Find the species that tick all the boxes below.
What Is A Nano Reef?
It depends a little on who you ask. Some reef-keepers consider everything smaller than 30 gallons to fall into the nano category. But in a 30 gal you still have dozens of suitable fish to choose from, which is why we consider true nanos (with limited fish options) to be 15 gallons or smaller.
We love a good nano, but it’s important to keep in mind that as the water volume shrinks, so does your room for error. There’s just less water to dilute any small mistakes, which can cause small fluctuations to become big problems. If this will be your first reef, you can buy yourself a lot of peace of mind by not going too small.
Aquariums of 5 gallons or smaller are sometimes called “pico” or “desktop” tanks. These are too tiny to keep any fish in, but if you can keep the water parameters stable, they can make an excellent home for coral frags and very small invertebrates.
What Fish Can Go In A Nano Reef?
Many of the species recommended for nano reefs (cardinalfish, dottybacks, grammas) can technically make do in a small tank. But they’re active fish that like a little swimming room, and we do think they look their best if you go the extra mile by getting them a 20–30 gallon home instead.
What does that leave us with? Gobies and blennies, of course! These perching bottom dwellers spend most of their time quietly observing instead of swimming around. In fact, many of them don’t even have swim bladders.
We’ve thrown in a few more active swimmers for you, but when it comes to nano reef fish, you’ll see the Gobiidae and Blenniidae reign supreme.
How Many Fish Can I Keep In My Nano Reef?
If there’s one thing we’ve learned in our years of setting up and running saltwater tanks, it’s not to overdo it. We all wanna catch ’em all, but overstocking a nano tank can be more trouble than it’s worth.
Depending on the size of your particular nano reef, your best bet to prevent water quality issues, bullying, and stressed fish is to limit yourself to 1–3 species. This way, everyone’s happy and the centerpieces can really shine.
If you’re worried your tank might end up boring, don’t forget you can also add invertebrates. There are plenty of tiny saltwater shrimp and snails, and also a few smaller (hermit) crabs that can work well.
Throw in a few micro brittle starfish and a good bunch of beautiful corals, and you’ve got a killer reef going without sacrificing half the living room.
Ocellaris Clownfish (Amphiprion ocellaris)
| Min. tank size | 10 gallons |
| Adult size | 3–4″ |
| Reef safe? | Yes |
The adorable ocellaris clownfish was a staple in the reef hobby even before Finding Nemo came out. It really is the ideal small saltwater aquarium fish: colorful, peaceful, reef safe, easy to keep and ever so wiggly. Need we go on?
Because ocellaris clowns rarely reach more than 3″ in length, you can keep them in compact aquariums as small as 10 gallons. Do keep in mind they’re best off as the only fish in desktop-sized tanks, because they’ll claim their territory and become cranky when anyone gets too close!
When picking up your clowns, be sure to go for a pair. Some aquarists keep them alone, but we think these little anemonefish truly come out of their shell when they’ve got their partner by their side.
Did you know? Having an anemone is not a must for your clownfish. A torch coral is easier to grow, and the fish will shack up with it just the same.
Pink Skunk Clownfish (Amphiprion perideraion)
| Min. tank size | 10 gallons |
| Adult size | 3–4″ |
| Reef safe? | Yes |
Ocellaris clownfish aren’t the only small clowns to consider. Although most types of anemonefish grow too big for a nano reef, the pretty pink skunk clown doesn’t tend to reach more than 3.5″ or so.
Care for a pink skunk clownfish is the same as for other clowns. You can give your pair a torch coral or anemone to host. They’re easy eaters that will happily accept pellets, frozen foods, and algae wafers.
In very small tanks it’s best to make your skunk clownfish the only fish inhabitants. In larger nanos around 15 gallons, they’ll get along well with one or two other small reef fish; as far as clownfish go, they’re very mellow.
Shrimp Gobies (Stonogobiops)
| Min. tank size | 10 gallons |
| Diet | Zooplankton and pods |
| Reef safe? | Yes |
There are many different species of shrimp gobies across multiple genera. Most, like the yellow watchman goby, need more space than a nano tank can offer. The tiny Stonogobiops, though, fit into a 10–15 gallon system just fine.
The best part? The goby’s best friend, the gunslinging pistol shrimp, can join your shrimp goby in a nano tank. Neither member of the pair moves around much, preferring to spend their time in the burrow the shrimp maintains for the both of them.
There are seven species of Stonogobiops shrimp gobies in total, all of which share their homes with shrimp in the wild. They’re very friendly and get along with everyone, even nano invertebrates like sexy shrimp that are normally on everyone’s menu.
Neon Gobies (Elacatinus)
| Min. tank size | 10 gallons |
| Adult size | Up to 2″ |
| Reef safe? | Yes, but perches on corals |
Now here’s a true microfish! Also known as the neon gobies, tiny Elacatinus gobies make up for their small size with big color. Some have a bright yellow or metallic blue streak running along their sides so larger fish know they offer cleaning services; others have vertical tiger bars and all sorts of fun patterns.
Neon gobies are hardy and make a good choice for first-time nano reefers. All they really ask for is clean water and a comfortable place to hang out. They perch on brain corals in the wild, but aren’t picky and will sit on any suitable ledge.
Tip: Elacatinus aren’t the only microgobies out there! If you’re looking for more tiny coral dwellers, keep an eye out for Trimma and Eviota gobies.
Flaming Prawn Goby (Discordipinna griessingeri)
| Min. tank size | 10 gallons |
| Adult size | 1.2″ |
| Reef safe? | Yes |
Here’s another goby that you’d simply lose in a larger aquarium: pictures don’t do justice to how small the flaming prawn goby really is. These flamboyant little fish were originally thought to pair with pistol shrimp, but are actually solitary and prefer rock crevices to burrows.
Flaming prawn gobies spend much of their days hiding in the tank’s rockwork. It’s frustrating when you just want to admire your expensive fish, but hey, you would hide too if you were only an inch long.
If you sit very still, your prawn goby might feel safe enough to come out and hunt. You’ll spot it darting around the bottom of the tank and flicking its beautiful fins as it hunts for copepods and amphipods. These gobies don’t really like prepared foods, so be sure to get the pod population started before you bring yours home.
Clown Gobies (Gobiodon)
| Min. tank size | 10 gallons |
| Adult length | Up to 2.5″ |
| Reef safe? | Yes, but perches on corals |
When it comes to tiny gobies, few genera are more beloved than Gobiodon (except maybe the closely related Paragobiodon). Also known as the clown gobies, the smallest species stay under an inch in length even as adults!
Aside from their suitability for desktop tanks, clown gobies are also just very charming to look at, with large heads and stumpy little faces. Their modified pelvic fins allow them to cling to any surface, and their colors range from bright yellow to black.
Like Elacatinus gobies, clown gobies like to spend their days perched on corals. This can irritate the polyps, but given they’re so small, it shouldn’t harm larger, healthy coral colonies.
Tailspot Blenny (Ecsenius stigmatura)
| Min. tank size | 10 gallons |
| Adult length | Up to 2.5″ |
| Reef safe? | Yes, but perches on corals |
Most of our favorite blennies (lawnmowers, anyone?) just grow too big for nano systems. But luckily, we don’t have to go completely without! The tailspot blenny, one of the best-looking of the bunch, also happens to be one of the smallest.
Like lawnmower blennies, tailspots have a taste for algae. Although they sometimes bother corals simply by sitting on them, they’re considered reef safe. They also get along well swimmingly with fish.
We’ve never seen a tailspot blenny bother absolutely anyone — except other tailspot blennies, which they hate with a burning passion. In a nano reef, you should definitely keep these colorful blennies by themselves or in a confirmed pair.
Possum Wrasses (Wetmorella)
| Min. tank size | 15 gallons |
| Adult length | Up to 3″ |
| Reef safe? | Yes |
Possum wrasses of the genus Wetmorella aren’t as elusive as flaming prawn gobies, but they definitely take the #2 spot. If you don’t mind a fish that spends most of its time hiding and hunting in the rockwork, these colorful and polite little wrasses are just the thing.
Some small wrasse species are territorial and can make their tankmates’ life difficult by constantly chasing them around the tank. Not possum wrasses. They’re shy more than anything else, and will stay out of the way of your other fish.
Like most small wrasses, possums are also reef safe. Do keep in mind they can struggle to understand how frozen and formulated foods work — you might have to start yours out on live pods, brine shrimp, and mysis.
Pink Streak Wrasse (Pseudocheilinops ataenia)
| Min. tank size | 15 gallons |
| Adult length | Up to 2.5″ |
| Reef safe? | Yes |
One of the most popular small wrasses in the aquarium hobby is the bristleworm-eating six line wrasse. It’s a beautiful fish, but it’s also bad-mannered. Luckily, it has a smaller and 100% peaceful cousin! The pink streak wrasse looks just as nice, leaves its tankmates alone, and should work well for reefs of 15 gallons and up.
Wrasses are active fish that like to swim around, but they mostly limit themselves to cruising around the rockwork. The trick to keeping yours happy in a smaller tank is to use lots of live rock, allowing it to spend its days exploring and searching for edible bugs.
Unlike six-lines, pink streak wrasses are peaceful and rarely bother their tankmates. Yours will get along swimmingly with one or two of the other fish mentioned here, though keep in mind it will eat small invertebrates.
Conclusion
A well-maintained nano reef is a joy to see, but needs regular maintenance to stay healthy. If you feel you don’t have the time or knowledge to care for the small saltwater aquarium fish mentioned here, we can help.
Contact FantaSEA Aquariums for the custom fish tank of your dreams: we’ll design, set it up, and maintain it for you. All you have to do is enjoy its natural beauty every day!
