Summary of How to acclimate new aquarium fish
- How long do fish need to acclimate?
- How do I acclimate my fish?
- How long should a fish tank sit before putting fish in it?
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AI Overview
AI Overview
To acclimate fish, use the Floating Method (float bag for temp, then slowly add tank water to bag over 30-60 mins before netting fish into tank, discarding bag water) or the quicker “Plop and Drop” (float bag for temp, net fish into tank, discard bag water) for hardier fish, ensuring lights are off to reduce stress. The more gradual Drip Method (using airline tubing to slowly add tank water to a separate bucket with the fish) is best for sensitive saltwater species or invertebrates, as it slowly adjusts pH and salinity. Always discard the shipping water to avoid introducing pathogens or ammonia spikes into your tank.
Method 1: Floating & Water Addition (Recommended for most Freshwater)
Turn Off Lights: Dim or turn off your aquarium lights to minimize stress.
Float the Bag: Place the sealed bag in the tank for 15-20 minutes to equalize temperature.
Add Water: Open the bag, roll down the sides, and add about 1/2 cup of tank water to the bag; wait 10-15 minutes.
Repeat: Add another 1/2 cup of tank water every 10-15 minutes (repeat 3-4 times) until the bag volume roughly doubles.
Release: Gently net the fish from the bag into the tank, ensuring you do not pour the bag water into your aquarium.
Method 2: Plop & Drop (For Hardy Fish)
Temperature Acclimate: Float the sealed bag for 15-20 minutes as above.
Transfer Fish: Turn off lights, open the bag, use a net to catch the fish, and place them directly into the tank.
Discard Water: Throw away the shipping water.
This video demonstrates the “Plop and Drop” method for acclimating fish:
52s
Cichlid Bros
YouTube · Nov 8, 2025
Method 3: Drip Acclimation (For Sensitive Saltwater/Inverts)
Set Up: Place fish in a clean bucket, float the bag in the bucket, and set up an airline tube drip line from the tank to the bucket (use a knot to slow flow).
Drip: Let the water drip slowly (2-4 drips per second) for an hour or more, adjusting flow and removing some water from the bucket as needed.
Release: Gently net the fish into the tank (again, discard bucket water).
This video shows how to set up and perform a drip acclimation:
55s
Dmm
YouTube · Oct 10, 2016
Key Tips
Turn off lights: during acclimation to reduce stress.
Never add shipping water: to your tank; it contains waste and can have dangerous pH swings when opened.
Never rush: the process; patience prevents stress and illness.
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How to acclimate new aquarium fish
If you are buying new fish or shrimp, they may be accustomed to water parameters that are very different from yours, and therefore you may want to slowly acclimate or get them used to your aquarium water. If the animals are small enough, you can acclimate them in a specimen container or bucket.
- Cut open the fish bag and pour the animals and some of the water from the bag into the catch cup so the fish are completely covered in water.
- Add aquarium water from their new home into the catch cup so that the water level is doubled. (If the water gets too high, just pour some out of the container.)
- After 15 minutes, add more aquarium water so the water is doubled again.
- After 10 minutes, add more aquarium water so the water is doubled again.
- Net the fish out of the container and add them to the aquarium.
For an even more gradual acclimation process, look up how to do “drip acclimation” using a length of airline tubing. If the fish are frantically dashing around in the catch cup, you can calm them down by darkening the room and/or covering the container with a towel.
If you purchased the fish online and they were shipped to you, you may want to use the “plop and drop” method instead. The reason is because ammonia and carbon dioxide from the fish’s waste and respiration may have built up in the bag, causing the pH to drop. When the fish bag is opened, the carbon dioxide is released and the pH rapidly rises, causing the ammonia to become toxic and burn your fish’s gills. To prevent this from happening, allow the fish bag to float in the aquarium for 10–15 minutes to acclimate them to the water temperature. (If the fish are in a breather bag that allows gas exchange, place the bag on the aquarium lid for about 30–60 minutes.) Place a fish net over a bucket, cut open the bag, and pour out all the water in the bag. Gently lower the net into the aquarium and let the fish swim out on their own. Any fish that have passed away will remain in the net for you to easily remove.