A 90-gallon tank is a suitably sized tank to host a large variety of saltwater fish, but it is not large enough to host every reef aquarium species.
Let’s dive a bit deeper and explore the best saltwater fish for a 90-gallon tank.
Saltwater fish that need 90-gallons as a minimum tank volume
Every aquarium fish on your list has a specific minimum volume of water or tank space to be healthy. Selecting a tank that is 90-gallons or larger doesn’t unlock a whole lot of additional fish vs. the 75-gallon tank, but it will help you unlock a few of the most desirable 8-inch and smaller tang species and several more of the Reef-safe wrasses and Fairy Wrasses:
- 8-inch Tang species (Yellow, Convict, Mimic) – all of these are with caution appropriate around 90-gallons
- Reef-safe Wrasses and Fair Wrasses (Exquisite, Mystery, Bluehead, Katherine’s, Scott’s)
Don’t forget these other popular fish with a 75-gallon minimum:
- Bristletooth tangs (Kole, Tomini, Squaretail, Two-spot)
- Dwarf Angelfish (Flame, Coral Beauty, Bicolor, and more)
- Anthias (Lyretail, Dispar)
- Basslets (Tobacco, Harlequin)
A list of the 92 Best saltwater fish for a 90-gallon tank:
- Reef Safe Wrasses: Mystery, Exquisite, Bluehead, Scotts, Katherine’s, Carpenter’s, Fairy, McCosker’s Melanurus, Yellow Coris, Sixline,
- Tangs: Yellow, Convict, Mimic, Kole, Tomini, Two-spot Bristletooth, Squaretail Bristletooth,
- Dwarf Angelfish: Flame angel, Coral Beauty, Bi-color, Pygmy/Cherub, Flameback, Lemonpeel, Rusty, Red Stripe,
- Antias: Lyretail, Dispar
- Reef safe wrasses: Carpenter’s, Lubbock’s Fairy, Melanurus, Yellow Coris, McCosker’s, Sixline
- Marine betta
- Dwarf lionfish: Fuzzy dwarf, Dwarf Zebra, Fu Manchu, or Monbasa
- Filefish: Aiptasia-eating
- Blenny: Tailspot, Two spot, Canary, Midas, Striped, Harptail or Smith’s
- Cardinalfish: Banggai, Yellow, Pajama, or Longfin
- Cleaner goby: Neon, Yellow line, Shark nose, or Hybrid
- Clownfish: Tomato, Cinnamon, Maroon, Clarkii, Spotcinctus, Ocellaris, Percula, Orange skunk or Pink skunk
- Chromis: Blue-green or Blue Reef
- Dartfish: Firefish, Purple firefish, Zebra, Scissortail orHelfrichi
- Pseudochrois: Orchid or Neon
- Fairy Basslet: Royal gramma, Blackcap or Chalk basslet
- Fancy goby: Clown, Two spot, Yasha or Court jester
- Hawkfish: Flame, Longnose, or Falco
- Puffer: Saddle Valenti (if fish only)
- Soldierfish: Squirrelfish
- Damselfish: Azure, Blue, Blue Devil, Bluefin, Blue Velvet, Domino, Three-stripe, Four-stripe, Yellowtail
A table of the 92 Best Saltwater Fish for a 90-gallon aquarium (scroll to see the whole table)
|92 Best Saltwater Fish for a 90-Gallon Tank||Options:|
|Tangs||Yellow Eye Kole||Tomini||Squaretail Bristletooth||Two-spot Bristletooth||Yellow||Convict||Mimic|
|Dwarf Angels||Bi-color||Cherub||Coral Beauty||Flame||Flameback||Lemon peel||Red Stripe||Rusty|
|Reef safe wrasses||Carpenter’s||Lubbock’s Fairy||McCosker’s||6 Line||Melanurus||Yellow Coris||Christmas|
|Dwarf lionfish||Fuzzy||Zebra||Fu Manchu||Monbasa|
|Clownfish||Cinnamon||Clarkii||Maroon||Ocellaris||Orange Skunk||Percula||Pink Skunk||Tomato||P. Skunk|
|Pseudochromis or Dottybacks||Neon||Orchid|
|Fairy Basslets||Blackcap||Chalk||Royal Gramma||Tobacco||Harlequin|
|Goby (other)||Clown||Court Jester||Two-spot||Yasha||Yellow Watchman|
|Damselfish||3 Stripe||4 Stripe||Azure||Blue||Blue Devil||Blue Fin||Blue Velvet||Domino||Yellowtail|
Typical 90-gallon tank dimensions
A 90-gallon tank is typically 48 inches long x 18 inches wide x 24 inches deep. That is nearly identical to the standard 75-gallon tank, except for the 3 extra inches of depth.
How heavy is a 90-gallon aquarium?
A 90-gallon aquarium will weigh 160 pounds empty and over 1000 pounds when full.
How many saltwater fish for a 90-gallon tank?
For fish-only, the total number of saltwater fish you should keep in a 90-gallon tank is 23 or fewer. Further restricting the number to 15 or fewer will reduce maintenance and increase your chance of success with corals and other invertebrates.
See the list below for recommendations about how many of each type of fish you could keep together. Keep in mind that not every single combination below is compatible. You should double-check your combination once decided:
- 3-5 Flasher or Fairy wrasses: Carpenter’s, McCosker’s, Exquisite, Mystery, Bluehead, etc.
- 1 Reef Safe Wrasse: Six line, Melanurus, Yellow Coris, Christmas
- 1 Small Tang: Yellow Eye Kole, Tomini, Squaretail or Two-spot Bristletooth, Yellow, Convict, Mimic
- 1 Dwarf Angelfish: Flame angel, Coral Beauty, Bi-color, Red Stripe, Pygmy/Cherub, Flameback, Lemon peel
- 1 Anthias: Lyretail, Dispar
- 1 Marine betta – my favorite fish of all time
- 1 Blenny: Tailspot, 2-spot, Canary, Midas, Striped, Harptail, or Smith’s – my personal favorite right now is the Canary
- 1-5 Cardinalfish: Banggai, Yellow, Pajama, or Longfin – gotta love Banggai cardinals, but beware of aggression
- 1-2 Cleaner goby: Neon, Yellow line, Shark nose, or Hybrid – it is possible to keep a pair (if male/female)
- 2 Clownfish: Tomato, Cinnamon, Maroon, Clarkii, Spotcinctus, Ocellaris, Percula, Orange skunk, Pink skunk
- 1-5 Chromis: Blue-green or Blue reef – beware, they tend to dwindle in numbers rapidly
- 1 Dartfish*: Firefish, Purple firefish, Zebra, or Scissortail, Helfrichi
- 1 Pseudochromis: Orchid or Neon – best to avoid the other Pseudochromis
- 1 Fairy Basslet: Royal gramma, or Blackcap, Chalk basslet, Tobacco, Harlequin
- 1 Other goby: Clown, Two spot, Yasha or Court jester
- 1 Hawkfish:Flame, Longnose, or Falco – okay only if you’re not keeping small inverts like crabs and shrimp
- 1 Filefish: Aiptasia-eating
- 1 Saddle Valenti puffer (if fish only)
- 1 Soldierfish: Squirrelfish
Alternatively, you could set up a predator tank with the following:
Damselfish are another potential option–although they can be aggressive.
A few notes and caveats about compatibility across the best saltwater fish
There are a few caveats to the recommendations above.
- Bluestreak cleaner wrasse technically has a 90-gallon tank minimum size, but they are really challenging to keep alive and are not fully recommended here.
- Fairy Basslets and Pseudochromis dottybacks likely won’t get along together.
- Dartfish are very mild-mannered, may not work with bold tank mates, best to be an early tank addition, if at all.
- Select either the Fairy, Flasher, or Reef Safe wrasses, not each of them. They won’t play nicely together.
- It is challenging to keep a shoal (>1) Chromis or (>2) Cardinalfish alive. For some reason (aggression), they tend to pick on each other until they dwindle in number.
- Soldiers and Hawks may eat your mobile invertebrates (crabs, shrimp, snails, etc.)
- I recommend starting with 1 of the Cleaner Gobies, although keeping a male/female pair is possible. If you have a pair, they’re easy to keep. However, if you need to establish a pair, be ready for some aggression between the fish of the same gender.
Equipment needed for a 90-gallon tank
- Heater – a single 300-watt heater will work. 2 x 200-watts is even better. Consider connecting them via a WaveBird for an added layer of protection and Peace of Mind.
- Protein skimmer – I recommend the Red Sea Skimmer. Read more here. The RSK-300 model or the RSK-600 are the two sizes to explore for a 90-gallon aquarium.
- Reef tank lights —Aqua Illumination is one of the most popular brands. Radion has a reputation for being the best
- Lid – Several saltwater fish listed here will jump out of tanks when startled. A tight-fitting lid is key or a screen that is sized exactly for your own tank dimensions
- 1 or more Powerheads are needed to create life-sustaining water flow in the tank
- Test kits – Water quality is so important—it pays to have the correct test kits
Other stocking options for your 90-gallon tank beyond saltwater fish
This article has primarily been about what fish are best for a 90-gallon tank, but there are undoubtedly other popular reef invertebrates you can and should consider adding to the tank with your beloved fish.
Here are a few other articles to help you start thinking through the rest of your stocking plan:
Some recommended reading beyond this immediate topic
Here are a few other essential articles to help you have success with your new saltwater tank:
- Find out which salt mix is the best for saltwater fish
- Learn how to make saltwater to achieve the proper water parameters
- See how much live rock do you need?
Saltwater fish recommendations for a different sized aquarium
If you want to see the advantages and disadvantages of the 90-gallon tank vs. some of the other sized tanks, check out the best saltwater fish recommendations for these different popular aquarium sizes:
- 75-gallon aquarium
- 55-gallon aquarium
- 40-gallon aquarium
- 30-gallon aquarium
- 20-gallon aquarium
- 10-gallon aquarium
Share your plans and leave a comment
After reading this article, what are your plans for your aquarium? Have you identified your livestock yet? Please leave a comment and let me know which of the 92 best saltwater fish for a 90-gallon tank you’re thinking about.