How to Acclimate New Fish
Proper acclimation is the difference between healthy fish and unnecessary losses. Learn the drip method and avoid the most common mistakes.
Why Acclimation Matters
Fish are sensitive to sudden changes in temperature, pH, and hardness. Shipping water often has different parameters to your aquarium, and dumping fish straight in can cause osmotic shock, stress, or even death. Proper acclimation gives their bodies time to adjust gradually, dramatically improving survival rates and long-term health.
The Drip Method
Place your fish and their bag water into a clean bucket. Using airline tubing with a loose knot to control flow, start a siphon from your aquarium into the bucket at a rate of roughly two to three drops per second. Over 30 to 45 minutes, the bucket water will gradually match your tank parameters. This is the gold standard for sensitive species like shrimp and wild-caught fish.
Temperature Matching
Before you begin acclimating water chemistry, float the sealed bag in your aquarium for 20 to 30 minutes. This equalises the temperature slowly without exposing your fish to tank water bacteria. Once temperatures match, you can begin the drip method or add small amounts of tank water to the bag every five minutes.
What Not to Do
Never pour shipping water into your aquarium. It contains ammonia from fish waste, potential pathogens, and dissolved medications from the supplier. Always net the fish out and discard the bag water. Avoid turning on bright aquarium lights immediately after adding new fish, as the sudden change from dark shipping bags to bright light adds unnecessary stress.
First 24 Hours
Do not feed your fish for the first 12 to 24 hours after arrival. They need time to settle, explore their new environment, and recover from the stress of shipping. Keep the lights dimmed and avoid tapping on the glass. Watch for signs of distress such as rapid breathing, clamped fins, or hiding, and test your water parameters to confirm everything is stable.
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