saltwater fish for 10 gallon tank

Saltwater Fish for 10 Gallon Tank

So what are the perfect saltwater fish for 10 gallon tank? a nano tank might be a great option if you don’t have much space at home. But what should you really be looking for when setting up a small saltwater aquarium in your property? Which saltwater fish for 10-gallon tank setups will work best, and can you introduce coral, too?

In this post, we’re going to be looking at the best fish in various sizes who live and thrive in 10-gallon tanks. As you may imagine, some of these fish will be pretty small species, such as nano fish! However, did you know that it’s possible to make a 10-gallon tank a great home for Clownfish, too?

Saltwater Fish Tank

Take a look at our guide below on 10-gallon tank setups, aquariums and what you need to know about the size and species of critters you’ll want to bring into the water. Whether you’re into saltwater shrimp or the odd colourful Goby, we’re here to help.

How Many Fish Can I Put in a 10 Gallon Saltwater Tank?

The general rule for any fish tank is that you try and account for about two gallons per one inch of fish. This means that you should ideally be looking to host around five inches of saltwater fish in a 10-gallon tank, at full growth.

This might not sound like much, but there are plenty of small fish out there who will help to brighten up any nano tank or 10-gallon aquarium. Nano tanks can come in various sizes, as can coral. However, it may still surprise you how roomy a saltwater aquarium can be.

It’s really important to make sure that your saltwater fish have as much space as possible to swim around and hide if need be. Tank size isn’t always something people consider too deeply at first.

10 gallons is a small tank in a way, but if you are just getting started with your own saltwater reef aquarium, it’s likely to be a fantastic starting point. You can always upgrade from a nano aquarium to a 30 or even 50 gallon aquarium at a later date if you really get on with reef fish such as the Royal Gramma, or other saltwater beasties such as the brine shrimp.

Can I Put 2 Clownfish in a 10 Gallon Tank?

This is really a matter of the type of Clownfish that you wish to host, as there are many different types! However, Clownfish can grow to be just over 4 inches in length when fully grown, meaning that while it might be fine for you to maintain a nano tank or similar for a pair of Clownfish while they are young, they are going to start running out of space the older they get.

Clownfish in Anemone, Great Barrier Reef 2 Photograph by Pauline Walsh  Jacobson

Captive bred Clownfish may grow or adapt differently, however, tank size is really important when your critters start getting to adulthood. A 20-gallon tank is probably going to be ideal for two fully grown Clownfish, whereas a nano tank that is any smaller might not be the best bet.

Choose a small tank initially if you are just starting out, but if you want to keep two or more Clownfish in the long run, try looking for 20 gallons plus.

Is a Saltwater Aquarium Hard to Maintain?

There are plenty of useful tips to maintaining a 10-gallon saltwater tank out there, meaning that while it’s fantastic as a hobby, there are still plenty of things you will need to keep in mind so that your fish and coral are nice and healthy.

Here are some top tips and tricks to try if you’re just getting started with a 10-gallon saltwater aquarium or tank for the first time:

  • Even small tanks are going to need regular salt checks, and by regular, we mean daily! It’s so important that the salinity of your water is up to scratch. It can actually increase by condensing unless you top up with warm fresh water every day.
  • Making saltwater isn’t something you will need to do every day, but it’s worthwhile keeping in mind how to do it when you need to. If your saltwater levels dwindle, be sure to top up with safely tested water. Your local fish centre or experts will be able to help you with this.
  • What’s more, try and scrub out algae every week. Algae can be a serious problem for your tank’s ecosystem, and while fish tend to produce it fairly often, it’s safe to say that you are going to need to keep on top of it.
  • Be smart about the fish you bring together in the same saltwater tank. A 10-gallon tank is going to be a relatively small unit for them, meaning you should make sure the buddies you bring together are at least compatible.
  • Keep checking your water quality – set up a regular regime, as you can’t often rely on this or spot the true quality by eye alone. Beyond this, always clean out your filters at least once a week.
  • If you’re bringing any fish or coral into a saltwater tank for the first time, you are going to need to fill it with water and let it run the nitrogen cycle for a few weeks before you do. This is because toxins in the water will need to convert to nitrates before you can safely add organisms into the mix.

Types of Saltwater Fish Great for a 10 Gallon Tank


As mentioned, Clownfish are ideal saltwater fish for a smaller to medium tank which will happily live alongside coral and live rock.

Clownfish in the Andaman Coral Reef
Clownfish in the Andaman Coral Reef

However, as mentioned, these aquarium fish can grow to be fairly large, meaning you should make sure to keep the numbers low or to look for a bigger tank if you foresee having more than one or two in the long run.

Clown Goby

Clown gobies are lovely fish which are nice and peaceful, and come in all kinds of colours and tints! They are also famously simple to look after. They are Gobiidae and will feed on other animals. Therefore, you should be careful to balance your home ecosystem out, as always!

Yellow clown goby Gobiodon okinawae
Yellow Clown Goby

Clown gobies are also pretty small, only ever growing to be about an inch and a half long. In a 10-gallon tank, you can probably expect to welcome up to three of them to adulthood, max.

Purple Firefish

The Purple Firefish is a really colourful and striking looking saltwater beast, otherwise known as the Nemateleotris decora. Like the goby, these fish are really simple to look after and to more or less leave to their own devices, though you’re naturally going to need to do the usual tank maintenance.

Purple Firefish, Nemateleotris Decora
Purple Firefish, Nemateleotris Decora

These lovely tank fish are also carnivores, though they are really peaceful creatures. Be aware, however, that they can grow to just over three inches long. In a 10-gallon tank, you’re likely going to be able to host one or two – so before they grow to adulthood, make sure to upgrade the size of your aquarium.

Neon Blue Goby

Neon Blue gobies are further variations on the popular and laid-back species observed above, though these fish particularly enjoy clean water, and you’ll really only have room for a pair of Neon Blues in a 10-gallon tank.

Neon Blue Goby
Neon Blue Goby

These gobies will eat pretty much anything, which can make them good tank mates, on the whole. However, as always, try and find a good balance in the community you bring into your tank. There may still be saltwater fish out there who will gladly snack on a Neon Blue.

Watchman Goby

The Yellow Watchman Goby is a popular choice for many home saltwater aquariums largely thanks to its golden hues. This means that any small tank likely to bring these beasties on board is going to be truly luminous!

Yellow Watchman Goby
Yellow Watchman Goby Source

They are laid back fish on the whole and are quite easy to look after and feed. However, they can grow up to four inches in length, which means you are effectively looking at only having space for one in a 10-gallon tank. It’s worth upgrading if you want to keep more.

Royal Gramma Basslet

The Royal Gramma Basslet is a really vivid looking fish that’s also ideal for saltwater! Again, due to their size at adulthood, you may only be able to safely house one or two in a 10-gallon tank before you need to start upgrading the size.

Royal Gramma Basslet
Royal Gramma Basslet

These yellow and purple aquatic critters are carnivorous and will happily live in your tank without kicking up a fuss.

Nano Fish

Nano fish is an umbrella term which covers all kinds of smaller fish that are ideal for small saltwater tanks and more. These can be guppies, betta, cichlids and more.

Golden guppies in tank
Golden Guppies

These fish are ideal for nano tanks as they only really grow to be two inches long at max. Take a look at what’s available from your local aquarium dealer.