The journey from shop to tank is one of the most stressful moments in a fish's life, and rushing it is a common cause of early losses. Proper acclimation lets new fish adjust to your water gradually and safely. Here's how to do it right.
Why Acclimation Matters
The water in the shop bag can differ from your tank in temperature, pH, and hardness. Dropping a fish straight in forces it to cope with a sudden change all at once, a shock that can be fatal even if the fish looks fine at first. Acclimation spreads that change over time.
Method 1: Float and Mix (Good for Most Community Fish)
- Turn off bright tank lights to reduce stress
- Float the sealed bag in your tank for 15–20 minutes to equalise temperature
- Open the bag and add a small amount of tank water every few minutes over 15–20 minutes
- Net the fish out and release it into the tank; do not pour bag water in
💡 Pro tip: Never add the shop water to your aquarium. It can carry disease, parasites, or poor water quality. Always net the fish across.
Method 2: Drip Acclimation (Best for Sensitive Species)
For shrimp, snails, and delicate fish, drip acclimation is gentler:
- Place the fish and bag water in a clean container below tank level
- Run airline tubing from the tank, tied with a loose knot to create a slow drip
- Aim for 2–4 drips per second
- Continue until the container volume has roughly doubled (about 30–60 minutes), then net the livestock into the tank
Quarantine: The Step Most People Skip
If you can, keep new fish in a separate quarantine tank for 2–4 weeks before adding them to your main tank. This prevents introducing disease to healthy fish and lets you observe and treat newcomers safely. It's the single best way to avoid a tank-wide outbreak.
Common Acclimation Mistakes
- Pouring shop water into the tank
- Rushing the process in under five minutes
- Acclimating under bright lights
- Adding too many new fish at once and overwhelming the filter
- Feeding immediately: wait until the next day so fish settle first
Find quarantine tanks, airline tubing, and water conditioners in our Aquatics range.
