How long should a quarantine treatment last?

It depends on the parasite or pathogen lifecycle. Ich and velvet treatments must outlast the parasite's free-swimming stage and typically run two to three weeks past the last visible spot, while bacterial and fungal courses follow the medication label. The calculator sets a disease-appropriate length.

Why does a water change come before re-dosing?

Most fish medications instruct a partial water change before the next dose to remove spent medication and waste, preventing overdose accumulation. The schedule places a water change on the correct days so each fresh dose starts from a known baseline.

How are doses scaled to my tank?

Medication labels give a dose per unit of water, commonly per gallon. The calculator multiplies that per-gallon dose by your tank volume so the schedule shows the actual amount for your tank rather than a generic figure. Always confirm against your product label.

Is this a substitute for the medication instructions?

No. It is a planning aid that builds a sensible rotation and reminds you when to dose and change water. Always follow the specific medication's printed instructions and a vet's advice, since active ingredients and concentrations vary between brands.

Should the quarantine tank have a heater?

Yes for ich and velvet — raising temperature speeds the parasite lifecycle so treatment clears faster, but only within the fish's safe range and with strong aeration since warm water holds less oxygen. The schedule notes temperature steps where they apply.

What is the Aquarium Quarantine Tank Protocol Calculator?

Select the disease — ich, velvet, bacterial, or fungal — and your quarantine tank volume to generate a day-by-day medication rotation schedule with doses scaled to tank size and a water-change cadence. For serious fishkeepers running a QT tank. Runs in your browser. It runs free in your browser on Gera Tools, with nothing uploaded.

Aquarium Quarantine Tank Protocol Calculator

Name: Aquarium Quarantine Tank Protocol Calculator
Creator: Gera Tools
License: https://creativecommons.org/licenses/by/4.0/

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A quarantine tank only works if you dose and change water on the right days for the specific disease. This calculator builds a day-by-day rotation — dosing days, water changes, and observation periods — scaled to your tank volume and matched to the pathogen you are treating.

How it works

Each disease has a treatment length and a dosing interval tuned to its lifecycle. The schedule is generated as:

for day = 0 to treatmentDays:
  if day mod doseInterval == 0:  water change (except day 0) → then dose
  dose amount = perGallonDose × tankGallons
  observe daily; extend if symptoms persist

A partial water change precedes each re-dose to clear spent medication, so doses never accumulate to a toxic level. Doses are scaled by multiplying the per-gallon figure for the disease by your tank volume, giving the actual amount to add.

Why each disease has a different schedule

The timing of water changes and re-doses is not arbitrary — it maps to the pathogen’s lifecycle. Ich (Ichthyophthirius multifiliis) and velvet (Oodinium) are only vulnerable to medication during their free-swimming tomont and dinospore stages. If you stop treatment before all the parasites have passed through that stage, the ones still encysted on the fish or the substrate will re-emerge and restart the cycle. Treatment must outlast the longest plausible lifecycle by a margin.

Bacterial infections work differently: the treatment length is set by the medication’s prescribed course, typically five to ten days, and stopping early risks resistance development.

An example ich schedule for a 10-gallon QT

Day	Action
0	First dose at the per-gallon rate for your product; start temperature ramp to 29 °C if fish tolerate it
2	Change 25 % water, re-dose for the full 10 gallons
4	Change 25 % water, re-dose
6	Change 25 % water, re-dose
8	Change 25 % water, re-dose
10	Change 25 %, re-dose; if no spots visible since day 6, enter observation
14	Final observation; if clear for 4+ days, treatment complete

This is illustrative — always confirm dose volumes against your specific product label. The tool generates the equivalent table for your tank size and disease.

Setting up the quarantine tank correctly

The medication schedule is only as good as the tank it runs in:

No carbon filtration. Carbon strips medication within hours. Use sponge or ceramic media only during treatment; seed it from your display tank in advance so the nitrogen cycle is established.
Aeration. Warm water and many medications reduce dissolved oxygen. Run a second airstone during treatment.
A thermometer. For ich and velvet, raising temperature speeds the parasite lifecycle and shortens treatment, but only within the fish’s safe range (species dependent). Monitor closely.
A lid. Stressed fish jump. Keep the tank covered.

When to extend

If you still see spots or lesions at the expected end date, extend the schedule rather than stopping. The calculator notes observation periods specifically for this: continue watching for a minimum of several days after the last visible symptom before declaring the fish clear.