How to Switch Fish to a New Aquarium

Moving fish to a new aquarium must be done carefully and correctly to avoid ammonia spikes and the possible death of your fish. Ammonia comes from fish waste along with uneaten food and can prove harmful, even fatal. In a properly cycled aquarium, healthy bacteria exists that breaks down this ammonia. New aquariums, however, lack this healthy bacteria since it lives under the surface of the aquarium water. This is why moving fish to their new home isn't as simple as just transferring the water from one aquarium to the other. It must be done in carefully planned steps.

Things You'll Need

  • Replacement water
  • Old aquarium toys
  • Four five-gallon buckets (you will need more if you have a lot of fish, or a large aquarium)
  • Fish nets
  • Siphon
  • Plastic shovel
  • De-chlorinator
  • New filter
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Instructions

    • 1

      Scrub the new aquarium to make sure it is clean and free of dirt or other debris. Wash any additions to the new aquarium.

    • 2

      Set up the aquarium in the permanent location you've chosen.

    • 3

      Wash the buckets to make sure they're clean and free of soap residue.

    • 4

      Place one of the buckets on a low stool or on the floor in front of the old aquarium Insert one end of the siphon into the aquarium water and point the other end toward the bucket. Suck gently on the lower end of the siphon tube. Wait until the water moves up the tube, past the edge of the fish tank and begins to flow toward the bucket. Take the siphon out of your mouth and allow the water to flow freely into the bucket. Stop the siphon when the bucket is getting close to full. Place your thumb over the end hole.

    • 5

      Capture your fish gently using nets. Place them into the buckets of old aquarium water. Continue to siphon the rest of the old aquarium water into the remaining until the aquarium is empty using the instructions from Step 4.

    • 6

      Using your plastic shovel, scoop the gravel from your old aquarium and place it in the new aquarium. Remove any plants or decorations with your hands. Add these to the new aquarium as well.

    • 7

      Slowly tip the water from the buckets without fish into your new aquarium. Attach your new filter to the new tank. Remove the filter from the old aquarium and also place it in the new one. When there is enough water to cover the filters, turn them on.

    • 8

      Once there is enough water in the new tank for the fish to swim freely, carefully and gently net the fish and transfer them out of the buckets. Add some de-chlorinated tap water if necessary. Refer to the label on the de-chlorinator additive you purchased, since they vary slightly in dosage.

    • 9

      Add the water from the fish buckets to the aquarium once you've moved all the fish. Top off the aquarium with more fresh de-chlorinated tap water.

    • 10

      Let the aquarium sit for at least thirty minutes after it's filled. Plug in the aquarium heater afterward and begin the process of setting the heater to the correct temperature.

    • 11

      Feed the fish infrequently for the next few weeks. Don't introduce any new fish for about one month. Allow the bacteria from the old filter to populate the new filter and let the fish become accustomed to their new home. Remove the old filter after two or three weeks.