17 Best saltwater fish for a 10-gallon tank

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

There 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

17 Recommended saltwater fish for a 10-gallon tank

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:

• 1 or 2 small, peaceful Clownfish ( Preferably Pink or Orange skunk due to their mild manners, but Percula and Ocellaris, 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 or Longfin)
• 1 Royal gramma

Clownfish (1 or 2)	Orange skunk	Pink skunk	Ocellaris	Percula
Fancy goby (1)	Clown goby	Court Jester	Two spot	Yasha
Cleaner goby (1)	Yellow line	Sharknose	Neon blue	Hybrid
Cardinalfish (1)	Longfin	Banggai
Royal gramma

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
• Heater
• Lights
  • For a fish-only aquarium, just about any aquarium light will work. You won’t need an expensive reef light

A few other related topics

Here are a few other articles that will help you start your new 10-gallon saltwater tank with success. 

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 shrimp, hermit crab, or a few coral frags as well. 

Check out:

Looking for a tank that is a little bigger?

If your space and budget allow, you might want to consider a slightly larger aquarium. If you’re interested in learning more, check out this companion saltwater fish stocking guide for a 20-gallon tank.