How to Set Up a Quarantine Tank on a Budget
A quarantine tank is the single most underrated piece of aquarium equipment. It prevents new fish from introducing diseases into your display tank, provides a safe space for sick fish to recover, and gives you a controlled environment for medication. This quarantine tank setup guide from Gensou Aquascaping at 5 Everton Park shows you how to build one cheaply and effectively.
Why Every Fishkeeper Needs One
New fish from shops may carry diseases, parasites or bacterial infections that are not yet visible. Introducing them directly into your display tank puts your entire collection at risk. A two to four week quarantine period catches most problems before they spread. The cost of a basic quarantine setup is a fraction of replacing a tank full of dead fish — or worse, losing a prized colony of breeding shrimp or rare fish.
Essential Equipment
Tank: A simple 20–40 litre glass or plastic tank is enough for most freshwater fish. Some hobbyists use large plastic storage containers — they work just as well and cost less. Expect to pay $10–$30.
Filter: A sponge filter is ideal. It provides gentle filtration, is cheap ($5–$10), and the sponge hosts beneficial bacteria. Keep a spare sponge running in your display tank filter at all times — when you need to quarantine, the pre-seeded sponge instantly provides a cycled filter.
Heater: A basic 50W heater ($10–$15) maintains temperature. In Singapore, this is only needed in air-conditioned rooms.
Air pump: To power the sponge filter. A small quiet pump costs $8–$12.
Hiding spot: A PVC pipe, terracotta pot or plastic plant gives the fish somewhere to hide and reduces stress. Avoid porous decorations that absorb medication.
What You Do NOT Need
No substrate — bare bottom is easier to keep clean and allows you to spot parasites and worm infestations. No expensive lighting — ambient room light is sufficient. No aquascaping — decorations absorb medications and complicate cleaning. No activated carbon in the filter — it removes medication. Keep it simple and functional.
Cycling the Quarantine Tank
The pre-seeded sponge method is the fastest approach. Keep a spare sponge in your display tank’s filter compartment. When needed, transfer it to the quarantine tank — it carries enough beneficial bacteria for an instant cycle. If you do not have a pre-seeded sponge, dose Seachem Stability daily during quarantine and perform daily 25 per cent water changes to manage ammonia.
Quarantine Protocol for New Fish
Acclimate new fish to the quarantine tank using the drip method. Observe for two to four weeks, watching for signs of disease: white spots (ich), rapid breathing, clamped fins, white stringy faeces, spots, ulcers or unusual behaviour. Feed normally and keep water pristine with regular water changes. Some hobbyists prophylactically treat with a mild anti-parasitic like Praziquantel during quarantine. After the quarantine period with no signs of disease, the fish can be acclimated into the display tank.
Using as a Hospital Tank
When a fish in your display tank shows signs of illness, move it to the quarantine tank for treatment. This protects healthy tank mates, prevents medication from affecting plants, invertebrates and beneficial bacteria in the display tank, and allows you to dose the right concentration in a smaller volume (saving money on medication). Always use the bare-bottom, decoration-free setup when medicating.
Storage Between Uses
When not in use, drain the quarantine tank, clean it with vinegar and water (never soap), and store it dry. Keep the sponge filter running in your display tank so it stays seeded with bacteria. This way, you can have a functioning quarantine tank ready within 15 minutes whenever an emergency arises.
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Still Have Questions About Your Tank?
Drop by Gensou Aquascaping — most walk-in questions get answered in under 10 minutes by someone who has set up hundreds of tanks.
5 Everton Park #01-34B, Singapore 080005 · Open daily 11am – 8pm
