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Discus Tank Size Calculator

Recommends minimum tank size in liters or gallons for keeping discus.

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Full grown length, nose to tail base, not the size it is today.

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This tool provides a general estimate and does not replace professional veterinary advice.

Updated · How we check our tools

What is the Discus Tank Size Calculator?

The Discus Tank Size Calculator recommends minimum tank size in liters or gallons for keeping discus. Undersized housing is one of the most common and most fixable welfare problems in pet keeping, it affects everything from stress levels to exercise to litter/waste management.

Discus generally live 10-15 years when they are well looked after. Diet-wise they are a carnivore, which shapes almost every feeding decision you make. Discus demand very warm, very clean soft water and near-daily water changes while growing. They are social and should be kept in groups of five or more. This is not a beginner species. The usual suspects for this species are hole-in-the-head disease, internal flagellates, bacterial infection from poor water, so any noticeable change is worth following up.

Discus quick facts

Reference values for discus from the species data behind this tool.
MeasureDiscus
Typical lifespan10–15 years
DietCarnivore
Mature atAbout 1.5 years
Clutch size150–300 eggs

How does the Discus Tank Size Calculator work?

The recommendation is based on published care-guide minimums for discus, scaled to the animal's current or expected adult size. It is a starting point, not a verdict. Somebody who has actually examined your discus will always know more than a formula does.

What changes the answer

  • Adult size: housing should be sized for the animal's full-grown dimensions, not its current size if still young
  • Number of animals being housed together, since space needs don't simply divide evenly
  • Activity level and natural behavior, such as climbing, digging or swimming space
  • Whether the space is temporary (travel/carrier) or permanent (everyday housing)

How do you use the Discus Tank Size Calculator?

  1. Enter the adult body length in whichever unit you use (in, ft, cm)
  2. Answer "How many of this species?"
  3. Pick your filtration and planting (Standard filter, no live plants, Strong filter or heavily planted, Minimal filtration)
  4. Press Calculate, then read the result alongside the sources listed below

If the result looks wrong, check your inputs before you worry. Entering weight in the wrong unit is easily the most common reason a figure looks off.

For related questions, see the other housing tools or browse every discus tool.

Before you rely on this

This calculation assumes a healthy adult discus with no complicating conditions. Pregnancy, recovery from illness, medication and significant age at either end of the scale all change what is appropriate. When in doubt, the safest move is to take the number to a vet and ask whether it fits your particular animal.

Sources and references

The formulas, reference ranges and species data behind the Discus Tank Size Calculator come from these veterinary references, professional bodies and published research.

  • Built on veterinary referencesFormulas and ranges come from veterinary manuals, university research and welfare bodies, listed above for you to check.
  • Instant resultsNo page reload, no waiting and no account. Enter your details and the result appears straight away.
  • Private by designCalculations run in your browser. Nothing you enter is stored on our servers or shared with anyone.
  • Always freeEvery XpertsPet tool is free to use, with no premium tier and nothing to sign up for.

Frequently asked questions

Is bigger always better?

Generally yes, within reason, the figure given is a minimum, not an ideal. More space typically means less stress and more natural behavior.

What if my current setup is smaller than recommended for my discus?

Plan an upgrade when practical, in the meantime, added enrichment and more frequent time outside the enclosure can help offset a smaller footprint.

Does the recommendation account for multiple animals?

Where the tool asks for a headcount, yes, but as a rule, space needs for discus don't simply scale linearly, so it's worth erring generous with groups.

What is the Discus Tank Size Calculator based on?

It uses published reference data and formulas from sources including RSPCA, Merck Veterinary Manual, PDSA Pet Health Hub. The full list, with links, is in the sources section above.