I am moving my Harlequin Rasboras, Neon Tetras, and Skirt Tetras from a (44 Liter)11.5 gallon tank to a (76 Liter) 20 gallon tank. I would like to know if I HAVE to bring the same gravel from the 11.5 to the 20 gallon. I will be adding about half of the water from the original tank to the new tank for bacteria reasons, but I will not be using the same filter. I just want to know if adding just the water from the old tank will be fine enough for my fish.

I would also like to know if I have to clean all the decor (and gravel if necessary) before I transfer it to the new tank. Thanks!

  • Hi, would you please stop removing metric unit conversions that had been included for convenience into your question? Please consider the fact that a lot of people there are more familiar with metric rather than imperial system. It's fine to use your familiar units of choice in your questions - but if someone is taking their time and effort to improve readability for metric-familiar part of the community and provides additional conversions, then removing them is not exactly the nicest thing to do - what is more, I think it could be considered disruptive. Thanks.
    – lila
    Jul 15, 2020 at 20:13
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    Oh my gosh, I'm so sorry, I had no idea this happened, I have been editing the post a bit, so the previous edits you made may have been reset. I will edit it to show what you have edited, again very sorry. Jul 15, 2020 at 20:20
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    Oh, so it was not intentional - I apologize for my tone then, maybe it was too harsh. Thanks for response and for including these conversions.
    – lila
    Jul 15, 2020 at 20:32

1 Answer 1


The way to do this is to setup your new tank, you do not need to move the old gravel, but you need to move some of the decor or filter media to your new tank; this is to seed your new tank with bacteria.

Do not move your fish to the new tank until it is properly cycled. Using some of the water from your old tank is not very helpful, the water contains very little of the bacteria you want so it is better to move some of the decor to your new tank. The bacteria you want live on all surfaces, so do not let it dry out and do not clean it.

Remember cycling a tank will take time so be patient and do not rush the introduction of your fish to the new tank.

Please take a look on how to cycle a tank properly in this article on fishlore.com.

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