aquanerd

Aquarium Stocking Calculator

How many fish can your tank actually hold? Pick a tank size and your livestock to see your stocking level and catch compatibility problems before you buy.

1. Your tank size

2. Add livestock

  • Cherry ShrimpPeaceful · 1.2"
    0
  • Amano ShrimpPeaceful · 2"
    0
  • Nerite SnailPeaceful · 1"
    0
  • Mystery SnailPeaceful · 2"
    0
  • Chili RasboraPeaceful · 0.7"
    0
  • Neon TetraPeaceful · 1.2"
    0
  • Ember TetraPeaceful · 0.8"
    0
  • GuppyPeaceful · 1.5"
    0
  • PlatyPeaceful · 2.5"
    0
  • MollyPeaceful · 4"
    0
  • Zebra DanioSemi-aggressive · 2"
    0
  • Corydoras CatfishPeaceful · 2.5"
    0
  • Kuhli LoachPeaceful · 3.5"
    0
  • Dwarf GouramiSemi-aggressive · 3.5"
    0
  • Betta (male)Territorial · 2.5"
    0
  • Pea PufferPredator · 1"
    0
  • AngelfishSemi-aggressive · 6"
    0
  • Bristlenose PlecoPeaceful · 5"
    0
  • Fancy GoldfishPeaceful · 8"
    0

Stocking level

0%

20-gallon tank · estimate, not an exact science

Tips

  • •Add a tank size and some species to see your stocking level.

Cycle the tank first and stock slowly. Need the gear too? Build a full kit →

How it works

  1. 1

    Pick your tank size

    From a 5-gallon nano to a 75-gallon community tank.

  2. 2

    Add your fish

    Choose species and quantities. We track bioload, minimum tank size, group needs, and temperament.

  3. 3

    Read the result

    A live stocking percentage plus warnings — overstocking, incompatible species, schooling fish kept in too-small groups.

How we estimate stocking

Each species has a bioload value (roughly the gallons it needs), based on its adult size and waste output. We add those up against your tank volume for a stocking percentage, then layer on real fishkeeping rules — minimum tank size, schooling group size, and temperament conflicts. It is a planning estimate, not an exact science: always cycle your tank first, stock slowly, and check each species’ full care guide for the details.