20 Gallon Long Aquarium Stocking Calculator

The 20 gallon long offers more floor space than a standard 20, making it ideal for corydoras, loaches, and active schooling fish. Calculate your bioload with the exact dimensions and see how much your filtration and planting affect capacity.

Aquarium Stocking Calculator

Calculate bioload, check compatibility, and plan the perfect stocking for your tank.

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Add your tank & fish

Your stocking score will appear here once you enter tank details and add some stock.

Aquarium Type

🌿Freshwater

Tank Dimensions & Volume

Length (in)

Width (in)

Height (in)

Calculated: 18.7 gal (70.8 L)

Volume (gal) — override for non-rectangular

18.7 gal(70.8 L)

Filtration & Setup

Filter Type

Filter rated gallons (optional)

Oversized filtration adds bonus capacity.

Plant density

Water change frequency

Substrate

Tank Age

Older tanks tolerate higher bioloads.

Stocking

Stock List

Popular species:

Search for fish, shrimp, corals and more to build your stocking list.

Save your stocking plans

Create a free account to track your tanks, log water parameters, and build your dream stocking list.

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Chat with Finn5 messages left

Hey! I'm Finn 🐟 Tell me what you're going for — like "a peaceful 20 gallon community" or "betta paradise tank" — and I'll set everything up for you. You can also ask me to analyze your plan once you've filled it in.