How to Move Fish From a Small Established Aquarium to a Larger One

Transferring fish from a smaller, established tank into a new larger tank requires the same preparation and attention to detail that is necessary when introducing new fish to a new tank. The ideal situation is to prevent the fish from becoming stressed during the transition, so that they can adapt to their new environment as safely and smoothly as possible.

Things You'll Need

  • Stress coat chemical enzyme
  • Tap water conditioner
  • Fish net
Show More

Instructions

    • 1

      Set up the new aquarium in its designated place, keeping it out of direct sunlight or away from a place where it might need to be moved later. Add the decorations and substrate of the aquarium, then set up the filter and aeration system. Fill the new tank with water.

    • 2

      Allow the new tank to mature for between five to seven days prior to the addition of the fish. During this time, add the necessary chemicals to the water to help acclimate the fish to their new environment. These chemicals include stress coat enzyme (a water dechlorinator) as well as tap water conditioner. Ensure that the temperature of both aquariums is the same, either at room temperature or with the same setting on the heaters.

    • 3

      Turn off the overhead lamp of both aquariums, then use the net to gently trap the fish from the old aquarium one at a time. Hold your hand over the top of the net to prevent the fish from jumping out, then quickly transfer the fish to the new tank. Continue in this manner until all the fish from the old tank have been transferred to the new tank. Leave the new tank's light off for several hours until the fish seem more acclimated to their new surroundings.