AquariumStocking ideas · checked against sources
What fish can go in a 125 gallon tank?
A standard 125 gallon tank is 72 × 18 × 21 inches. Of the 106 species in our database, 94 fit comfortably and 6 are a tight fit, based on each species' sourced minimum tank size and group size.
Stocking combinations that pass every check
Each set was run through the tank builder's rules: tank size, temperature, pH, hardness, predation, fin-nipping, temperament and stocking level. Treat them as starting points, not prescriptions.
- 15 × Boesemani Rainbowfish5.2 in adult
- 5 × Angelfish7.1 in adult
- 1 × Japanese Trapdoor Snail2.6 in adult
Stocking about 62% · shared temperature 81–85°F
Open in tank builderStocking about 26% · shared temperature 77–81°F
Open in tank builderStocking about 70% · shared temperature 70–75°F
Open in tank builderFish that fit a 125 gallon tank
Tetras & rasboras (25)
- Neon Tetra1.4 in adult · group 8+
- Cardinal Tetra1.7 in adult · group 8+
- Harlequin Rasbora2.1 in adult · group 8+
- Ember Tetra0.9 in adult · group 8+
- Chili Rasbora0.9 in adult · group 8+
- Celestial Pearl Danio1 in adult · group 20+
- Rummy-nose Tetra2.4 in adult · group 10+
- Black Neon Tetra1.7 in adult · group 8+
- Glowlight Tetra1.9 in adult · group 6+
- Lemon Tetra1.9 in adult · group 8+
- Zebra DanioNeeds care2.4 in adult · group 8+
- White Cloud Mountain MinnowNeeds care1.9 in adult · group 10+
- Black Skirt Tetra3.5 in adult · group 12+
- Bleeding Heart Tetra2.9 in adult · group 8+
- Congo Tetra3.8 in adult · group 6+
- Diamond Tetra2.8 in adult · group 6+
- Giant DanioOutgrows tanks3.5 in adult · group 8+
- Head-and-tail-light Tetra2.1 in adult · group 6+
- Lambchop Rasbora1.4 in adult · group 8+
- Pearl Danio2.6 in adult · group 8+
- Penguin Tetra1.7 in adult · group 6+
- Pristella Tetra2.1 in adult · group 6+
- Scissortail RasboraOutgrows tanks7.1 in adult · group 6+
- Serpae TetraNeeds care1.9 in adult · group 12+
- Silver Tip Tetra2.4 in adult · group 6+
Livebearers (6)
- Guppy2.8 in adult · group 6+
- Platy2.4 in adult · group 6+
- Endler's LivebearerNeeds care1.2 in adult · group 6+
- MollyNeeds care3.8 in adult · group 6+
- SwordtailNeeds care6.6 in adult · group 6+
- Variatus Platy2.4 in adult
Barbs (6)
- Cherry Barb2.4 in adult · group 6+
- Tiger BarbNeeds care2.8 in adult · group 8+
- Denison BarbOutgrows tanks5.2 in adult · group 6+
- Gold Barb3.5 in adult · group 8+
- Odessa Barb2.2 in adult · group 8+
- Rosy Barb4.7 in adult · group 8+
Gouramis & bettas (8)
- Honey Gourami2.6 in adult · group 4+
- Dwarf GouramiNeeds care4.2 in adult
- Pearl Gourami5.7 in adult
- BettaNeeds care3.3 in adult
- Moonlight Gourami7.1 in adult
- Paradise FishNeeds care3.8 in adult
- Sparkling Gourami1.9 in adult · group 2+
- Three-spot GouramiNeeds care7.1 in adult
Cichlids (10)
- German Blue RamNeeds care1.9 in adult
- Bolivian Ram3.8 in adult
- Kribensis4.7 in adult
- AngelfishNeeds care7.1 in adult · group 5+
- Blood Parrot CichlidOutgrows tanks8 in adult
- Cockatoo Dwarf Cichlid3.5 in adult
- DiscusNeeds care6.6 in adult · group 6+
- Electric Blue AcaraNeeds care7.1 in adult
- Electric Yellow LabNeeds care4.7 in adult · group 4+
- Firemouth Cichlid5.7 in adult · group 2+
Catfish & plecos (12)
- Bronze Cory3.5 in adult · group 6+
- Panda Cory2.4 in adult · group 6+
- Pygmy Cory1.4 in adult · group 6+
- Julii Cory2.6 in adult · group 6+
- Sterbai Cory3.2 in adult · group 6+
- Bristlenose Pleco5.9 in adult
- OtocinclusNeeds care1.7 in adult · group 6+
- Clown Pleco4.2 in adult
- Glass Catfish3.1 in adult · group 6+
- Peppered CoryNeeds care3.3 in adult · group 6+
- Pictus CatfishOutgrows tanks5.7 in adult · group 6+
- Upside-down Catfish4.7 in adult · group 3+
Loaches (3)
- Kuhli Loach4.7 in adult · group 6+
- Hillstream LoachNeeds care3.1 in adult · group 6+
- Weather LoachOutgrows tanks13 in adult · group 3+
Shrimp & snails (11)
- Cherry Shrimp1.6 in adult · group 10+
- Amano Shrimp2 in adult · group 6+
- Nerite Snail1 in adult
- Mystery Snail2 in adult
- Assassin Snail1.3 in adult
- Bamboo Shrimp4 in adult · group 6+
- Crystal Red Shrimp1.5 in adult
- Ghost Shrimp2 in adult · group 6+
- Japanese Trapdoor Snail2.6 in adult
- Malaysian Trumpet Snail3.1 in adult
- Ramshorn Snail1.2 in adult
Others (13)
- Boesemani Rainbowfish5.2 in adult · group 6+
- African Dwarf Frog1.4 in adult · group 2+
- Bumblebee GobyNeeds care1.7 in adult · group 6+
- Chinese Algae EaterOutgrows tanks13 in adult
- Clown Killifish1.6 in adult · group 8+
- Dwarf Neon Rainbowfish3.8 in adult · group 6+
- Forktail Blue-eye2.8 in adult · group 8+
- Marbled Hatchetfish1.7 in adult · group 10+
- Pea Puffer1.4 in adult
- Rainbow SharkOutgrows tanks7.1 in adult
- Red-Tail SharkOutgrows tanks5.9 in adult
- Siamese Algae EaterOutgrows tanks7.1 in adult · group 6+
- Silver Hatchetfish1.9 in adult · group 6+
Tight fit (just under a sourced minimum)
Popular fish that outgrow it
- Bala SharkOutgrows tanksNeeds 96 in long / 228 gal
- Clown LoachOutgrows tanksNeeds 72 in long / 170 gal
- Common / Comet GoldfishOutgrows tanksNeeds 39 in long / 42 gal
- Common PlecoOutgrows tanksNeeds 71 in long
- Iridescent SharkOutgrows tanksNeeds 177 in long / 3850 gal
- Tinfoil BarbOutgrows tanksNeeds 83 in long / 200 gal
Gear sized for 125 gallon
Tank72×18×21 inFind on Amazon →Heater2 × 300 WFind on Amazon →Filter500–750 GPHFind on Amazon →Test kitLiquid kitFind on Amazon →
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Common questions
How many fish can go in a 125 gallon tank?
It depends on adult size and waste output, not inches per gallon. The combinations on this page stay under about 80% of a sensible load for 125 gallons in our estimate.
What fish outgrow a 125 gallon tank?
Popular examples include Bala Shark, Clown Loach, Common / Comet Goldfish, Common Pleco, Iridescent Shark, Tinfoil Barb.
What heater size does a 125 gallon tank need?
About 2 × 300 W, using roughly 5 watts per gallon.