10 gallons (37.9 liters) can be a nice size for a first saltwater tank or…a second saltwater tank. It is small enough to fit just about anywhere. The “biggest” problem with a 10-gallon tank is that it is on the small side–but that doesn’t mean you can’t still have a great saltwater tank. Some of the recommendations here are fairly similar to those for a 20-gallon tank.
Let’s refine that strategy a bit to eliminate some of those that won’t be suitable in a tank half of that size.
10 Gallon tank dimensions
The most common dimensions of a standard rectangular 10-gallon tank are 20 in. x 10 in. x 12 in.
| Length | Depth | Height |
| 20 in. (50.8 cm) | 10 in. (25.4 cm) | 12 in. (30.5 cm) |
How to determine the best fish for a 10-gallon tank
A 10-gallon tank is a fine size to start a reef tank at home, but selecting the right fish is an important step. Many of the saltwater fish species you will find at local fish stores start out small but grow to sizes that are unsuitable, others simply require more open space than 10-gallons of volume can provide, and a few others are just notoriously challenging to care for.
For all of those reasons, we want to narrow down the list to a few target marine fish types that are going to thrive in the environment you create for them. But first, let’s clear the deck of a few options. Identifying which aspects to eliminate as possibilities will also help us be more sure about the selections you will make.
Selecting fish types that are the right size for the tank–as juveniles and adults
The first way to select the best fish for a 10-gallon tank, we have to limit our choices to the fish that are the right size for the tank. This can be tricky at times because it not only means selecting fish that are the right size today but also will be the right size when fully grown (if not fully grown already).
For example, the blue tang is sometimes sold when it is 3/4 to 1.5 inches in length. They are adorably cute Dory’s, but they grow up to be quite large and are not suitable for 10-gallons. No snowflake eels, no maroon or tomato clownfish, no Picasso triggerfish or Clown triggerfish, etc. Being a big fish in a small pond may work for your career, but it doesn’t work if you’re the big fish and the pond is a 10-gallon saltwater tank.
Skip the fish that need lots of room to swim
You wouldn’t keep a horse fenced into a townhouse yard, you also don’t want to keep the open-water swimmers fenced into a 10-gallon tank. There simply is not enough territory to explore and graze to keep them happy. If you tried that, you would be almost guaranteed to have problems. If you have your heart set on keeping any of the types of saltwater angelfish (even the dwarf species), reef safe wrasses, any of the various types of tang, or butterflyfishes, you will want to invest in a much larger tank. Even the wildly popular and inexpensive green chromis probably isn’t a great choice–they are small–but need room to swim.
Avoid the fish that require expert experience
The relatively small volume of a 10-gallon tank doesn’t allow much wiggle room for error. As such, I recommend you steer clear of the hard-to-care-for species, like Scooter Blennies, or Mandarinfish. They are the right size, but they need a lot of TLC. Let’s focus on species that are more likely to give you great success.
The best saltwater fish for a 10-gallon tank
The best saltwater fish for a 10-gallon tank:
- Peaceful
- Small in size (4-inches or less when fully grown–smaller-the-better)
- Natural habitat is a small piece of the reef
- Slow-swimmers or like to perch on rocks vs. swim around all-day
25 Best saltwater fish for a 10-gallon tank community
| Species and number of fish (1-5 fish) | Option 1 | Option 2 | Option 3 | Option 4 |
| Clownfish (2) | Pink skunk | Orange skunk | Ocellaris | Percula |
| Fancy gobies (1) | Clown | Court jester | Two-spot | Yasha |
| Cleaner gobies (1) | Neon | Yellow-line | Sharknose | Hybrid |
| Blennies (1) | Tailspot | Two-spot | ||
| Cardinalfish (1) | Banggai | Longfin | ||
| Basslets (1) | Royal gramma | |||
| Damselfish (3-5) – in damsel-only tank | Azure | Blue | Blue devil | Blue velvet |
| Damsels (continued) | Three-stripe | Four-stripe | Yellow-tail |
The best plan for stocking saltwater fish for a 10-gallon tank would be to pick 5 fish or fewer, in total, from the following options and create a healthy, compatible community saltwater tank:
- 1 or 2 small, peaceful Clownfish ( Preferably Pink or Orange skunk due to their mild manners, but and Ocellaris and Percula (like Picasso) are okay
- 1 Fancy goby: Two spot, Yasha, Two-spot, Court jester or Clown goby
- 1 Cleaner goby: Neon variety- Yellow-line, Hybrid, Sharknose or ‘True” Neon (blue-striped)
- 1 Small blenny (Tailspot, Two spot)
- 1 Cardinalfish (Banggai, Longfin)
- 1 Royal gramma
If you’re looking at this list and were hoping for a few more options, check out the stocking guides for these other tank sizes:
- Best fish for a 15-gallon saltwater tank
- 20-gallon tank saltwater fish recommendations
- Best fish for a 30-gallon tank
- 40-gallon tank stocking guide
- 50 gallon tank guide
- 55 best fish for a 55-gallon tank
- 75 gallon aquarium
- 90 gallon aquarium
- 100-gallon aquarium dimensions, weight and best fish
By using this list, you will have selected small, peaceful fish and have created a community aquarium. But that is also not your only option, there are several great fish types that will do well in the confines of the smallish 1o-gallon tank that are not ideally suited to be part of a community. I’m writing about the damselfishes.
Damselfish-only for a 10-gallon saltwater tank
Damselfish are nearly perfect for the home aquarium. They are vibrantly colored, hardy, and typically inexpensive. Their one fatal flaw, when it comes to community tank living, is that they are aggressive–some of them downright pugnacious. One of the other problems with aggression between fish is that it isn’t always consistent, however, one could expect a damselfish in a small community tank to bully one or more of the fish in the tank to the point where they jump out or succumb to starvation.
But on a bright note, something almost magical happens when you add a few-to-several aggressive fish together at the same time, the aggression spreads out and gets reciprocated, and you can often achieve a balance/harmony.
So another great option for a 10-gallon tank is to fill it with damselfish. You could add 3 to 5 brilliantly colored damselfish from the following list:
- Azure damselfish
- Blue damsel
- Blue Devil
- Blue Velvet
- Three stripe
- Four stripe
- Yellowtail
That brings the total list up to 25 of the Best saltwater fish for a 10-gallon tank.
How many saltwater fish can be in a 10-gallon tank?
You can keep 1 to 5 small saltwater fish in a 10-gallon tank from a list of fish suitable for this size aquarium. Keeping more than 5 will result in a greater risk of problems and maintenance needs.
Can 2 clownfish be kept in a 10-G aquarium?
The smaller clownfish species: Orange skunks, pink skunks, ocellaris & Percula can be kept in pairs in a 10-G (37.8L) aquarium and may even breed in an aquarium this size, as long as the water quality is maintained sufficiently through maintenance and monitoring.
Can you use a 10-gallon tank for saltwater?
A 10-gallon saltwater tank is called a nano and is suitable for keeping small corals, invertebrates, and saltwater fish. Special care is required for selecting the right animals who will thrive in an environment of this size.
Equipment needed for a 10-gallon saltwater tank
You will need the following equipment:
- Lid
- To prevent fish from jumping out when startled–believe it or not, this happens A LOT
- Water flow and aeration
- Filter
- Either sponge, hang-on-back, canister, or Live Rock
- Heater
- Lights
- For a fish-only aquarium, just about any aquarium light will work. You won’t need an expensive reef light
10 Gallon tank cost
The standard, no-frills rectangular 10-gallon tank will sell at retail for about $20, but can be found on sale for around $10. A higher end all-in-one-system like the Waterbox Cube 10 costs ~$220.
A few other related topics
Here are a few other articles that will help you start your new 10-gallon saltwater tank with success.
- Picking the right salt mix
- Maintaining the right water quality
- How to make saltwater?
- How to set up a saltwater tank?
- How much live rock do you need?
Other stocking options
This article focused on the best saltwater fish for a 10-gallon tank, but there are some other saltwater tankmates you could keep. Remember, 10-gallons doesn’t provide a ton of space, but you could certainly consider adding a small peppermint shrimp, a trochus snail, hermit crab, or a few small corals like candy cane, torch or hammer frags as well.
Check out:
Best saltwater fish for larger tanks
If you are looking for something a bit larger than 10-gallons, check out these other great stocking guides for larger tanks:
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