So, I want to get fish again at some point, and I have loads of gravel from the last time. Problem is, it's probably not clean.

I know there are likely things I can't do to clean it because that will then harm any new fish, but how can I ensure it is clean and free of any dirt or decayed plant/fish matter? In the past I have just rinsed it multiple times with warm water using a sieve or the like to keep the gravel from going down the drain.

  • Have you tried a gravel vacuum?
    – Mozein
    Oct 6, 2014 at 21:22
  • @Mozein A gravel vacuum is great for stuff in the tank, Ashley indicated this was just gravel she had stored after her last tank, and has been dry for quite some time.
    – Tim Post
    Oct 7, 2014 at 4:50
  • @TimPost she can put them in any container and vacuum or just vacuum them before adding the fish and plants. Great to see there are answers now though.
    – Mozein
    Oct 7, 2014 at 5:33

2 Answers 2


If you're going to be re-introducing gravel that has been in 'dry dock' for quite a while, your best option is to simply give it a few minutes in boiling water, and then rinse thoroughly. This kills any:

  • Mold
  • Organics (from insects, rodents, spores, etc)
  • Anything and everything else

It'll also help to loosen up any dirt or debris that you wouldn't want slowly released in the tank after being submerged again. It basically brings the gravel back to the condition that it was in when you first took it out of the bag.

Don't use any detergents or chemicals, if your tap water is high on the chlorinated side then consider boiling and rinsing with distilled instead.

Just make sure that you rinse it thoroughly after boiling, and allow it to return completely to room temperature prior to using it again. Once back in the tank, it can begin accumulating the beneficial stuff, at which point you'd use a gravel vac to remove the unwanted particles that tend to accumulate at the bottom of the tank.



Didn't read the OP thoroughly enough. I would agree with boiling the gravel because it is the safest way to ensure any harmful bacteria have been killed. Unfortunately this kills anything left behind that is good as well.

You could rinse the gravel with warm water in a colander if you desire and then try the following to keep it clean:

The best option once your tank is setup is a gravel vacuum. You can get the right one depending on the size of your tank.

Here is a link on Amazon for a good gravel vac for 10 gallons and under however there are good options for bigger tanks.

These will suck up particulate like waste food and feces that you don't want. They are also pretty safe for fish if you use them right.

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  • I'm guessing the gravel has been sitting dry for a while, so there's really no bacteria to kill. Gravel vacuums are good to have though.
    – Spidercat
    Oct 7, 2014 at 0:20
  • 1
    @MattS. Drying does not necessarily kill all bacteria, Endospore in particular are known to survive dry for as long as 25 million years Oct 7, 2014 at 11:45

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