Moving Fish to a New Tank: How to Upgrade an Aquarium

Rasbora Fish in an Aquarium

Upgrading to a larger tank is usually a good option if your floor can take the weight of the additional water. Larger aquariums are simpler to keep clean, and you can keep more fish in them! Here are the procedures to effectively transferring everything from your existing smaller aquarium to a larger one.

Preparing the Old Aquarium for Exit

If the aquarium has just had a big event, such as fish death, filter media change, or the addition of new fish, it's best to wait a few weeks before making this aquarium transfer. This will help the old aquarium to recover its equilibrium.

Beneficial bacteria populate the filter medium, as well as the gravel bed and all other aquarium hard surfaces, such as rocks and ornaments. All fish, as well as all décor, equipment, and gravel, can be relocated without being washed, although most of the old water should be left behind.

Setting Up the New Aquarium

You'll need a larger filter and heater to accommodate the new system. Because the old equipment will not be powerful enough for the greater size, new equipment must be rated for the larger tank volume. If you want to utilize the old filter in the new tank, keep the smaller tank's beneficial bacteria alive by running it.

Fill the new tank only three-quarters full of water to start. This will allow enough displacement capacity to accommodate the new equipment, gravel, and any decorations. In the new tank, run an to assist disperse any dissolved gases that may be present in your water supply. Allow 24 hours for the new system to run.

Testing the Water to Match

To avoid stunning the fish, both tanks must be heated at the same time to provide equivalent temperature conditions. Because aquarium heaters occasionally fail, your old heater can be used as a backup.

The pH and of the old aquarium should be tested and recorded. Test the pH and temperature in the new tank after 24 hours of settling; compare your results. If there is a pH variation of more than two tenths of a point or a significant difference in between the two tanks, do not proceed with the transfer.

Of these two parameters, pH is the more critical. Adjust the pH of the new aquarium up or down just as you would in the old one.

Moving the Gravel and Filtration

Use a clean cup to transfer the gravel from the old tank to the new one. Next, move all the rocks and decorations. If you plan to use the old filter in the new tank, move it at this time.

The filter material in the old tank's filter contains helpful bacterial colonies. You may introduce lots of helpful bacteria to the new system by running both the old and new filters for a few weeks. This additional filtration will also aid in the establishment of the new aquarium.

Before transporting the fish, make sure all filtering systems are operational. Treat the new aquarium as you would any other, which entails testing the water for ammonia and nitrite on a daily basis and performing partial water changes until they reach zero.

Moving Your Fish 

You can move fish without needing to bag them if the pH and water temperature are precisely the same; use a clear plastic pitcher with a barrier on top. Otherwise, you may bag the fish and acclimatize them just like any other fish you buy and bring home.

To catch each fish, submerge the pitcher and gently lead the fish inside with a little net. Hold a lid over the top to prevent the fish from jumping out, then carefully lower the pitcher into the new tank, but do not poor or spin the pitcher; allow each fish to acquire its bearings and swim out on its own. Once the fish have been transported to the new aquarium, check that all of the components (warmer, filter, lighting) are operational and that the water quality is within acceptable limits. Then you can relax and enjoy your new, larger aquarium!


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