Best Saltwater Fish For 20, 30, 50-Gallon Tank

By Harry RamosLast update: 2024-05-25
Best Saltwater Fish For 20, 30, 50-Gallon Tank

When it comes to saltwater fishes, buyers have got an avalanche of choices. But the decision-making process isn’t as easy as it seems because there are lots of things to consider.

Aside from their characteristics and care requirements, one important thing you should keep in mind is the tank size required for them to live happily inside. In this article, I am going to give you a list of the best saltwater fishes for 20-, 30-, and 50-gallon tanks.

For 20-Gallon Tanks

Purple Dartfish (Also Known As Purple Firefish)

Best Saltwater Fish For 20, 30, 50-Gallon Tank

This is a very peaceful and easy-to-keep fish for beginners.

They highlight bright red, yellow, and purple fins, purple faces, and a mixture of iridescent yellow or white bodies fading to gray near the tail. Compared to other species, this is a super-thin fish with a wide range of personalities.

Due to its max length of 4 inches, Purple Dartfish is perfect for a 20-gallon saltwater tank.

There are two solid things you should remember when keeping them:

  1. Feed them with a vitamin-enriched diet for color fading prevention
  2. Add a tight-fitting lid to the tank because Purple Dartfish can jump

Besides, it’s best to have some rock rubber in your tank because this fish loves hiding into tight crevices.

Yellowtail Damsel

Best Saltwater Fish For 20, 30, 50-Gallon Tank

While most damselfish are arguably pretty aggressive, this isn’t a thing. Although they’re semi-aggressive, Yellowtail Damsel still lives peacefully with other species.

They look colorful and beautiful with a yellow with a bright blue tail.

The best thing about these fish is that they’re hardy and do fine in most saltwater conditions (as long as you remain proper water parameter ranges) and can live as a single species or in schools. Plus, they’re omnivores.

Whether pellet food, flake, dry meaty foods, or frozen foods, they accept like a breeze.

Royal Gramma Basslet

Best Saltwater Fish For 20, 30, 50-Gallon Tank

This is another easy-to-care fish for beginners. They aren’t struggling to adjust themselves to a new tank like other species and moreover, Royal Gramma Basslet doesn’t require super-clear water conditions.

As their maximum length is only 3 inches, this fish is perfect for a 20-gallon tank.

They’re also considered as peaceful fish with different species but sometimes, they may be found to be aggressive with other Basslets.

Additionally, they might eat smaller invertebrates if not fed enough because this fish is carnivores. Their favorite diet is a mixture of Mysis shrimp and brine shrimp.

Don’t forget to add rocks to your tank to provide an ideal hiding place for them.

For 30-Gallon Tanks

Chalk Bass

Best Saltwater Fish For 20, 30, 50-Gallon Tank

Although Chalk Bass is carnivore and semi-aggressive, they’re very easy to keep and care for. They even live well in less than optimal water conditions and won’t eat sessile invertebrates or corals.

Besides, their colorful body adds beauty to your saltwater tank.

If you intend to keep more than one Chalk Bass in a 30-gallon tank, make sure to introduce them at a time to prevent territorial fighting.

Like most other species, remember to add a lot of rocks to your tank for hidden spots.


Best Saltwater Fish For 20, 30, 50-Gallon Tank

Similar to Chalk Bass, this is a small carnivore fish and considered semi-aggressive. But if you provide them with a good diet, various hiding places, and the right tank size, they will live non-confrontationally and happily with other species.

Just remember to introduce them to others at the same time so they won’t fight each other.

The biggest selling point of Dottyback is that they’re hardy and easy to care for, which comes in handy for beginners in learning how to keep their fish properly.

Besides, Dottyback comes in a wide range of colors, such as bicolor, yellow, purple, and blue.

Diamond Goby

Best Saltwater Fish For 20, 30, 50-Gallon Tank

If you’re looking for a peaceful, hardy, and easy-to-care carnivore fish for your 30-gallon tank, Diamond Goby is a flawless candidate.

While they are quite timid, the average lifespan of Diamond Goby is quite long and the best part is they help clean sand. The reason is this fish loves to burrow in the live sand substrate as a refuge.

But you should take note that they are highly terrestrial. To prevent them from fighting each other, make sure to introduce them at a time or add a mated pair.

For 50-Gallon Tanks

Yellow Coris Wrasse

Best Saltwater Fish For 20, 30, 50-Gallon Tank

Also known as Canary Wrasse, Golden Wrasse, or Golden Rainbowfish.

This small carnivore fish is very easy to care for because they’re hardy. They also live peacefully with most other fish, including their own species. By eating pyramidellid snails, parasites, and fireworms, they protect clams and corals pretty well.

The only thing you should keep in mind if you choose to keep this fish is Yellow Coris Wrasse is very active and they can jump.

Make sure the tank size is at least 50 gallons with a tight-fitting sealed lid. Besides, prepare at least 3” sandy substrate for them to hide.

Six Line Wrasse

Best Saltwater Fish For 20, 30, 50-Gallon Tank

For those fish keepers who are on a tight budget, this is a great choice to add beauty and lively looking to your reef tank without flattening your wallet.

Six-Line Wrasse is very colorful, easy to care, and active. They’re a carnivore and semi-aggressive so despite their modest size, this fish requires a spacious tank size to live non- confrontationally with other species.

The fish is probably found to act aggressively towards other easily-intimidated fish or other Wrasses.

But if you provide them with a peaceful environment, create as many hiding spots as possible, and feed them adequately, it will be okay.


Above are the best saltwater fishes for 20-, 30-, and 50-gallon tanks. Although there’s still a lot of other species out there, these are the hardiest and easiest to care about. Hopefully, you find this article is helpful, and thanks for reading!

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