9 Small Saltwater Fish For A Nano Tank

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In my opinion, nano tanks are greatly under-appreciated. Some of the most amazing saltwater tanks are small in size and true showpieces. Nano tanks are basically a small tank that is less than 30 gallons. If you are looking to start a nano tank, it’s important to research the types of fish that are suitable for a small tank ahead of time. Nano tanks are limited to the types and sizes of livestock you can have. Smaller tanks are less forgiving with respect to water quality and you will need to be cautious of how you decide to stock the tank.

Here are 9 small saltwater fish that are great for a nano tank.

  1. Clownfish
  2. Blue/Green Chromis
  3. Firefish Goby
  4. Bangaii Cardinal
  5. Neon Goby
  6. Watchman Goby
  7. Lawnmower Blenny
  8. Filefish
  9. Flame Hawkfish





Clownfish are probably the most popular choice for a nano tank. There are so many types of clownfish available and they can live in pairs which many people love to have in a small tank. Combined with an anemone, a pair of clownfish makes a stunning tank.  Most clownfish stay small and only grow to a maximum of 3-4″”. They are very active and colorful, generally not aggressive and are reef safe. A common clownfish for nano tanks are the Ocellaris and Percula.

Clownfish are also easy to feed and will accept a combination of frozen and live foods. They will also eat pellets and flakes. If you decide to have a pair of clownfish, it is recommended that you have a minimum of 20-gallon tank size.


Blue/Green Chromis



The Blue/Green Chromis are another great choice for a nano tank. They are a small fish that will only grow to about 2″ and do well in groups. They are very colorful and peaceful towards others. They are reef safe and won’t bother any corals or invertebrates.

The Blue/Green Chromis are considered to be a tough fish and are great for beginners as well. They are easy to feed and will accept a variety of foods.



Firefish Goby



The Firefish Goby is sometimes called a Dartfish and is known to have an interesting personality. It has amazing coloration and a pronounced forward dorsal fin which makes these fish stand out from the pack.

These fish are very timid when you first introduce them to the tank. After a few days, they will become more comfortable and active. They are called Dartfish for a reason. They can move quickly and dart very fast when chasing food or hiding from threats. The Firefish is a peaceful fish and make a great addition to a nano tank.

A few things to be cautious of when considering a Firefish Goby:

They can starve themselves to death if they feel threatened or stressed. They also require a sand-based substrate as they like to dig. It’s also important to note that these fish love to jump and will leap out of your tank in a blink of an eye. Therefore make sure you have a very secure lid or canopy on your tank with no areas for them to jump through. They are notorious little jumpers.


Bangaii Cardinal



They Bangaii Cardinal is one of my favorite fish and is great for smaller nano tanks around 20 – 30 gallons. It is a very interesting looking fish that have black stripes and white dots. They are generally peaceful and will get along as pairs. The Bangaii is one of those fish that can easily breed under the right conditions.

They are a slow-moving fish that will move in all areas of your tank. They are reef and invertebrate safe. The Bangaii can be difficult to feed when introduced to a new tank, but it won’t take long for them to accept a variety of pellets, flakes, and frozen foods. They are generally available from your local saltwater fish store and are not an expensive fish to purchase.


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Neon Goby



The Neon Goby is a great little fish for nano tanks and actually has a job to perform in your tank. They will help clean the other fish from small parasites. This is very common and interesting to see. The Neon Goby is a peaceful fish but can sometimes fight with other gobies. They will naturally establish a territory in the tank, so it’s a good idea to have lots of rock and hiding places for them.

They are not overly colorful but have a stripe of blue on top of a black body. These fish will not bother any corals and are considered reef safe. They are also easy to feed and will accept a variety of meaty foods including pellets, flakes, and frozen.


Watchman Goby



The Yellow Watchman Goby is one of the most interesting fish you can have in a small tank. They have a unique characteristic. They form a special bond with Pistol shrimp and help each other out with respect to bullies and predators. The Goby will alert the shrimp of potential danger and will use the shrimp’s cave for protection. They are amazing to watch together.

The Watchman Goby is a peaceful fish towards others. The exception would be with other gobies. Other than a mated pair, different gobies can fight and act aggressively towards each other. They are reef and invertebrate safe and are easy to feed. They are commonly found in most fish stores and are inexpensive to purchase.


Lawnmower Blenny



The Lawnmower Blenny is also known as the Rock Skipper fish and can be seen jumping between rocks. They are a small fish that are popular to see in nano tanks. They are generally used as part of the cleanup crew in your tank to help control algae. They are great at “mowing down” hair algae.

These fish are not overly colorful but do have a distinct look. They remind me of some kind of lizard or crocodile. The Lawnmower Blenny is a peaceful fish, but you must be careful if they are mixed with the same species. They will become aggressive.

If they run out of algae to eat, you will have to supplement their food with algae sheets which they will accept. It’s important to note that these fish are not considered reef safe, they can nip at corals and also bother invertebrates and clams.






The Filefish is also known as the Aiptasia eating filefish as they can be seen eating, you guessed it, Aiptasia! These fish are easy to care for and are great for beginners. They are also a small fish that will do great in a nano tank.

The Filefish is not very colorful and have a camouflage look to them. They also have very rough skin and can feel like sandpaper. They are peaceful fish and usually won’t bother other tankmates. It is possible that they will pick at invertebrates, so be aware of that. Also, know that the Filefish is not reef safe. So if you have corals in your tank, you may want to rethink purchasing a Filefish.

Although the Filefish will eat Aiptasia, they are accepting of other foods. This includes shrimp, squid, scallops, krill, and marine algae. They are considered carnivores and are not overly picky with food. A mix of pellets and frozen foods combined with algae will work well for them.


Flame Hawkfish


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The Flame Hawkfish is a very colorful fish that includes a bright red body and a black stripe going down it’s back. They have a distinct personality and are known to be very peaceful and playful. They are not a fast swimmer and in fact they don’t swim much at all. They prefer to hang out in caves or perched on rocks.

The Hawkfish will accept a variety of foods. They are not picky. They are not aggressive with other tankmates but you have to watch them if mixed with certain invertebrates like shrimp, snails, and crabs. They have a tendency to pick at them.

If you plan to start a nano tank, give the Flame Hawkfish a try. They are one of the most interesting fish to watch and are very popular to see in saltwater tanks.


Small saltwater fish for nano tanks FAQ’s


What does nano tank mean?

A nano tank is just a smaller sized saltwater tank usually under 30 gallons in size.

What is the smallest sized tank for a clownfish?

A 10-gallon tank is the smallest tank you should consider for 1 clownfish. If you have a pair, then 20 gallons is the minimum size.

What is the best nano tank?

The Coralife Biocube is my favorite nano tank which is an all in one aquarium system.