For Perfect Results Cleaning Aquarium Decorations

Last Updated on July 4, 2021 by cmoarz

If you have an aquarium, it is very important that you know how clean the decorations, this includes hardscape and decorative plants. In this article, I go over some tips and tricks to ensure that you are doing the best job possible, as well as doing it in the safest way possible for you and your fish.

Printable Infographic Bellow!

How to clean aquarium ornaments and plastic plants

TL;DR For Skimmers

For a simple wash that retains beneficial bacteria, Soak the ornament in dechlorinated water and brush with a toothbrush. For sterilizing, mix 2 ounces of unscented plain bleach with 4 gallons of water. Let soak for 20 minutes, scrub, rinse in dechlorinated water.

Cleaning aquarium décor should be part of your bi-annual *big* routine maintenance.

It’s not something that needs to be done regularly, like water changes and wiping down the glass, but light maintenance can go a long way to keeping your tank looking its best.

It’s good to keep in mind that even though the bulk of your good bacteria are inside your filter, There’s plenty that attaches itself to your decorations as well.

Cleaning them will kill this bacteria, however, as long as you have some remaining in the filter there’ll be more to replace it. So it’s not something you should worry about too much.

Before we begin, You will need:

  • A small bucket, 5 quarts should be good, But if you’ve got a lot of decorations, feel free to use as big as you need, even 5 gallons.
  • (Optional:) A second bucket to place your dirty ornaments in.
  • Water conditioner. Any will do. Fill the bucket with your usual water change tap water and add the water conditioner. This will remove the chlorine and will be the water you use to rinse off your decorations once you have finished cleaning them.
  • A toothbrush or other scrub brush. Lots of nooks and crannies. (Unused except for this purpose)

None Sterilization Directions

Assuming you just want to give them a quick clean, and there is no reason to go further such as sterilizing them with chemicals Than do this:

  • Take the ornaments out of the tank. If this is a planet tank, be careful not to accidentally uproot any living plants.
  • Place them to the side, Or in the optional ‘dirty’ bucket.
  • Take a bit of aquarium water out of the aquarium and put it in a bowl.
  • Take your brush and wipe away all the algae and grime.
  • Give it a final rinse in fresh aquarium water, or dechlorinated tap water.

This method will retain most of the good bacteria in the ornaments, and not harm your fish. Special thanks here need to go to the water dechlorinator. Even trace amounts of chlorine can kill giant swaths of bacteria in your tank and filter, causing your tank to start to cycle again.

If you are in the market and want to try new things, Here is our favorite brand of water conditioner.

Complete Sterilization Directions (Cleaning with bleach)

Sometimes you need to do full sterilization. That could be for a variety of reasons, the most common being a bacterial outbreak or disease. Luckily, A full sterilization of your decorations is easy.

  • Take the ornaments out of the tank.
  • Take a 5-gallon bucket of tap water, none conditioned (it doesn’t matter here), and mix in 2 ounces of unscented bleach with no additives to 4 gallons of water.
  • Allow decorations to sit in the solution for 20 minutes or so. Repeat to get the really hard stuff off.
  • Scrub with your brush until everything seems to have come off. Make sure you get every nook and cranny, it’s important for full sterilization.
  • Rinse your decorations off with regular tap water, make sure you get all the bleach solution out.
  • Now rinse them again inside your dechlorinated water bucket. This will remove any that’s stuck in the decoration.
  • Your decor is now fully sterilized!


Don’t leave your ornaments in the bleach solution for more than 40 minutes. It will begin to erode the surface and they will become brittle. They may also begin to fade in color or lose their color altogether depending on what they are made of.

Metal decorations shouldn’t be put in bleach. In fact, metal decorations shouldn’t really be in your aquarium at all, to begin with, Especially copper.

Don’t dip live plants into bleach solution. If you need to sterilize your plants, there are other ways to do this or simply replace them if the need is that urgent, such as in the case of disease.

You can clean decorations in bulk but they won’t get the necessary attention to detail if you had done them individually. You should also not take all decorations out of the tank at the same time without a resting period in between if the tank is stocked. What I’ve found works best is 25% give it a day 25% give it a day and then do the last 50%.

The exception is if you’re battling an outbreak of something.

Cleaning Aquarium Decorations Without Bleach

There are alternatives to bleach if for some reason you just can’t use it, or you just don’t want to. You can use hydrogen peroxide or vinegar. You should only use one of these at a time, not both together. EVER. Cleaning aquarium decorations with vinegar is by far one of the more popular methods.

You can also use regularly treated water with a simple scrub brush. Allowing it to sit likely will have no effect, however, and you may not be able to get the harder algae if present.

Fish That Clean Your Decorations For You

Nature also has a way to clean your decorations. Assuming your aquarium isn’t already fully stocked and they are compatible with your current water parameters, You should consider getting one of these:

  • Cherry shrimp
  • Siamese Algae Eater
  • Mystery Snail (Warning, they lay a lot of eggs!)
  • Nerite Snail
  • Trumpet Snails (Also lay a lot of eggs)

These are all species that will help keep your ornaments cleaner for longer periods of time without any extra labor from you. They all do a great job of eating algae off of decorations, although don’t expect miracles either. Eventually, you may still need to clean them.

Should you clean aquarium decorations before first use?

Some people will say yes, and some will say it doesn’t matter.

My personal preference is yes, I give it a good rinse in treated tap water before I put them into the tank. No chemicals necessary, but a good water rinse will make sure no loose plastic or dust will contaminate my water clarity or affect my inhabitant’s health.

So it’s a good precautionary measure to take when putting in new decorations from the store.

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Owner of and also owner of actual Aquarium Gravel believe it or not! ;). Setting up beautiful aquarium sceneries and habitats since I was very young. Enjoy!