How many saltwater fish in a 50 gallon tank

One thing that frustrated me when I was looking to set up my first saltwater tank was how challenging it was to interpret all of the advice to figure out which saltwater fish to choose and how many were appropriate for my tank.

This guide will explore the best saltwater fish for a 55-gallon tank. I also know that many people are searching for a 50-gallon tank. The recommendations here will also broadly apply to a tank that size, if you can find one, or if you have one built, custom. A 55-gallon saltwater tank is a more common standard size near me (Eastern U.S.).

Typical 55-gallon tank dimensions

A 55-gallon tank is typically 48in. Long x 13 in. wide x 21 in. deep. 

It is a relatively large tank, but they are still commonly available at most pet stores. They are a good value because they are right at the threshold where you can still pay $1/gallon during a sale. Tanks above this size tend to be a bit more expensive and stay more expensive.

The shape and volume of the 55-gallon tank are quite suited to establishing a healthy saltwater aquarium. The 4-foot length looks excellent up against any wall in your home or apartment and gives fish a bit more room to spread out and swim about, which opens up saltwater fish options you wouldn’t have with a smaller size. 

48 in. x 13 in. x 21 in. are the typical dimensions of a 55-gallon tank

If those dimensions don’t seem quite right for the space you have available in your home or apartment, you may want to check out these other tank stocking guides:

• 90-gallon tank recommendations
• 75-gallon tank dimensions and guide
• 40-gallon saltwater fish stocking guide
• 30-gallon guide
• 20-gallon aquarium plans
• 10-gallon saltwater fish plans

As mentioned above, a 50-gallon tank is possibly/probably a rare or custom item. Other websites reference dimensions of 36 in. x 18 in. x 19 in. So if you like the overall footprint of a tank that size but have a hard time finding it, check out the 40-gallon breeder tank, which is a standard and routinely available size, with the same length and width. It is 3 inches shorter, but neither you nor the fish will miss it. 

The key to creating a thriving community aquarium is to pick non-aggressive saltwater fish from different families that look different and occupy other spaces in the aquarium. All of the fish recommended in the stocking guides for smaller tanks will work in a 55-gallon setting, and the extra room allows you to select from a few more fish families.

List of 56 best saltwater fish for a 55-gallon tank and my recommended number of fish:

Below are two lists that include the 55 best saltwater fish for a 55-gallon tank. The tank’s footprint this size gives you a lot of flexibility in the fish you can have. If you exclude the incompatible combinations – like dotty backs and basslets or clownfish and chromis, dwarf lionfish, and anything small enough to fit in its mouth, you could probably have one fish from each category, for a total of ~15-18 fish max. That’s a lot of fish, which means a lot of fish waste, which means more difficulty keeping corals. So consider restricting to ~9 or so if you want to have corals. These are just approximate.

Having a tank that is 50 gallons to 55 gallons is the threshold volume recommended to keep:

• 1 Dwarf Angelfish (Pygmy/Cherub, Flameback – now available Captive-bred!)
• 1 Reef safe wrasses (Carpenter’s, Melanurus, Yellow Coris, McCosker’s, Sixline)
• 1 Marine betta – one of my favorite fish ever!!!
• Dwarf lionfish (Fuzzy dwarf, Dwarf Zebra, Fu Manchu, Mombasa) – WARNING–do not keep with community fish

Plus, you can keep these other great saltwater fish suitable for 40-gallons or less

• 1 Aiptasia-eating filefish (if you have aiptasia or love them)
• 1 Blenny (Tailspot, Two spot) or 1 Fangtooth blenny (Canary, Midas, Striped, Harptail)
• 1 Cardinalfish (Banggai, Yellow, Pajama, or Longfin) 
• 1 Cleaner goby (Neon, Yellow line, Shark nose, or Hybrid) or a pair
• 1-2 Clownfish of the same species—you can even pick from the larger species as well ( Tomato, Cinnamon, Maroon, Clarkii, Spotcinctus, Ocellaris, Percula, Orange skunk, Pink skunk) or 1 Green chromis as an alternative to clownfish
• 1 Dartfish (Firefish, Purple firefish, Zebra, or Scissortail, Helfrichi)
• 1 Dottyback or 1 Fairy Basslet (Orchid or Neon…I don’t recommend the others)
• 1 Fairy Basslet (Royal gramma, or Blackcap) or Chalk basslet
• 1 Fancy goby (Clown, Two spot, Yasha or Court jester)
• 1 Hawkfish (Flame, Longnose, or Falco)
• 1 Saddle Valenti puffer (if fish only)

If you have a deep sand bed, you could consider:

• Either 1-2 Engineer gobies (blennies)
• or 1-2 Jawfish (Yellowhead or Blue spot) 

Here’s the same information listed as a table below of the 56 Best Saltwater Fish for a 55-gallon tank:

Incompatible pairings

With most of the fish species in this list, except where indicated otherwise, it is generally best to keep just 1 from a group because similar species often will quarrel with each other.

You will also find that certain groups don’t mix, like chromis and clownfish, dotty backs and basslets, blennies, and some gobies. Wrasses and gobies. Be sure to check out the specific species profiles after consulting this overview to make sure your pairing is a fit, and be sure to share your experiences if you have pairings that don’t work.

Damselfish and aggressive fish

Most damselfish species will also be suitable for a 50 or 55-gallon tank – a few of the most popular species are:

• Azure
• Blue 
• Blue Devil 
• Bluefin
• Blue Velvet 
• Domino
• Three Stripe or Four Stripe
• Yellowtail 

The only problem with damselfish is that they are often a problem…when kept with other community saltwater fish. They are feisty, aggressive little critters. Ironically the best way to deal with that is to pack them all together. So if you want to keep damselfish, consider keeping a damselfish only tank and mix and match to your heart’s content. A 55 gallon tank could house a lot of damsels–perhaps 15 or more. 

55-gallons is also the minimum size you would need to keep dwarf lionfish. The only problem with dwarf lionfish is that they like to keep community fish. That’s why I am talking about them in this section.

Equipment needed for a 55-gallon tank

• Heater – 200 Watts should be sufficient
• Protein skimmer
• Reef tank lights
• Lid
• Powerhead
• Test kits

A few essential related topics to consider

I hope this article gave you a few ideas about some of the best fish for a 30-gallon saltwater tank. As you know, this is just the beginning. There are many other topics to cover. Here are a few other critical articles to help you have success with your new saltwater tank:

• How to make saltwater?
• Picking the best reef salt mix
• Step by step guide on how to set up a saltwater tank
• How much live rock do you need?
• The 9 Most important water parameters

Other stocking options

Fish are possibly the easiest and most readily available animals you can keep in your 30-gallon saltwater tank, but they are far from the only thing you can keep. Liven up your tank with:

• Beginner corals
• Cleaner shrimp options
• Invertebrates

Share your plans and leave a comment

After reading this article, what are your plans for your 55-gallon tank? Have you picked your livestock yet?

Pin me on Pinterest

How many saltwater fish can I put in a 55

What saltwater fish can you put in a 55

How many fish can be in a saltwater tank per gallon?

How many saltwater fish can I put in a 40 gallon tank?