Care guide
How to cycle your aquarium
Cycling is the single biggest reason first fish die. It takes three to six weeks and costs almost nothing — do it before you buy, not after.
What cycling actually means
You are growing bacteria in your filter that turn toxic fish waste into something harmless. Until that colony exists, any fish in the tank is being poisoned.
- Ammonia (toxic) → nitrite (toxic) → nitrate (harmless in small amounts)
- The bacteria live in your filter media, not the water
- Never wash filter media in tap water — chlorine kills the colony
The fishless cycle, step by step
Set the tank up fully — heater, filter, substrate, plants — then feed the bacteria with a source of ammonia.
- Fill and dechlorinate, run the heater at 26–28°C
- Dose bottled ammonia to 2–3ppm (or drop in a pinch of fish food)
- Test every 2–3 days with a liquid test kit; strips are not accurate enough
- Nitrite will spike, then fall; keep re-dosing ammonia as it drops
How to know it's done
Your tank is cycled when it processes a full ammonia dose in 24 hours with no nitrite left behind.
- Ammonia 0ppm and nitrite 0ppm within 24 hours of dosing
- Nitrate readable (usually 10–40ppm)
- Do a 50% water change, then add fish
Speeding it up
You cannot skip the cycle, but you can shorten it.
- Add mature filter media or a squeeze of dirty sponge from an established tank
- Live plants absorb ammonia and help from day one
- Bottled bacteria helps somewhat — still test before adding fish
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