How To Clean Aquarium Decorations To Get Rid Of Nuisance Algae

Cleaning aquarium decorations can be frustrating because algae are stubborn. Even using a course brush is not always enough. Removing algae from decorations is easy using any of the methods below.

Boiling water and vinegar solutions are gentle methods that work well for soft algae.

For tougher algae, try citric or muriatic acid. They are more corrosive to break down the unwanted green stuff.

For truly tough algae, try a dilute bleach solution. It may cause some discoloration, though it’s highly effective.

Whatever solution you choose to use, NEVER use soap.

Regardless of the method you choose, remember to use protection.

Always wear gloves — even when working with plain water or vinegar. The gloves create a safety barrier between the solution and the skin.

Don’t go anywhere near the aquarium with the cleaning solutions. Always clean the decorations in a container separate from the tank.

Before cleaning, thoroughly wash your hands. Ensure no soap or lotion is on your hands or anything else that may harm the fish.

Note that these methods are only suitable for non-living decorations, like plastic plants. Don’t place living plants in these solutions, or they are likely to die.

There are similar solutions for sterilizing new live plants. These solutions are slightly different than the ones for cleaning decorations.

Only Clean A Few Decorations At A Time

Avoid cleaning all the decorations at once, as removing them all is stressful for fish.

Decorations are also home to beneficial bacteria. Removing all the decorations at once may throw off the aquarium’s delicate ecosystem.

Clean Decorations In A Separate Container

Never clean decorations in the aquarium when using a solution, as the solutions are toxic to fish.

Some aquarists scrub their decorations in the tank before a water change.

Using a gravel vacuum to suck up the loosened algae once it’s come off the decorations is easy. Scrubbing in the tank often works well for soft, easy-to-remove algae.

We recommend removing the decorations, even if only using water. Removing the decorations minimizes fish stress and makes the tank easier to clean.

Use A New Bucket Or Container

Rather than cleaning inside the tank, use a 5-gallon bucket or large plastic tote.

It’s best to start with a brand-new container to ensure no harmful residue is inside it. Thoroughly scrub and rinse used containers before using them to ensure they’re safe.

Use A Sink

Some aquarists wash their decorations in their sink. It’s okay to do this as long as there is no soap in the sink that can get on the decorations.

Thoroughly rinse the sink before using it to get rid of any soap. Rinse the decorations afterward to remove any soap that may have been missed.

Soap is deadly for fish and invertebrates and should never be in the tank.

Clean the sink with soap or disinfectant after using it to clean the aquarium decor. The decorations may harbor zoonotic disease or bacteria.

Use Scrubbing Tools

Don’t use a steel or wire brush since they’re highly abrasive and can damage the decorations.

Toothbrushes, toilet brushes, and bottle scrubbers are great for removing algae. The fine bristles can get in the hard-to-reach areas of decorations.

Never use brushes that are used for cleaning other things around the house. Leftover chemicals on the brush can kill the fish. The bacteria left behind from the fish can be harmful to humans.

Buy brand new brushes for the aquarium and only use them for the aquarium.

Pick A Safe Sponge

Take care when picking a sponge. Many household sponges contain toxic cleaning agents. It’s best to choose a sponge explicitly designed for aquarium use to be safe.

Even sponges with antimicrobial agents are bad for fish tanks. While they may not be toxic to the fish, they kill off the good bacteria in the tank. Without good bacteria, waste transforms into toxic ammonia and nitrites.

Use Protective Gear

Aquarists should keep themselves safe when working around fish tanks and strong solutions.

We recommend using rubber cleaning gloves when cleaning a fish tank, even if only using water. While it’s rare, humans can contract zoonotic diseases from their fish. Don’t expose bare skin to fish tank water.

Rubber gloves are essential when working with a chemical solution to clean decorations. Some of these solutions are abrasive and can cause skin damage, especially bleach.

It’s for the same reason aquarists should always wear protective eyewear. Splashing may occur and cause damage to the eyes.

Use Hot Water

Hot water alone is often enough to get decorations clean. Many prefer this method because it involves no chemicals, making it safe for fish. While it works great for most dirt, it’s rarely effective enough for algae.

Here’s how to clean decorations with boiling water:

1. Boil a large pot of water.
2. Transfer the boiling water to a 5-gallon bucket or container.
   1. Make sure to use oven mitts to prevent burns.
3. Place the decorations in the water.
4. Repeat steps one and two until enough water covers all the decorations.
5. Allow the decorations to sit for at least 10 minutes.
6. Scrub the decorations with an algae sponge or brush to get stubborn debris.
7. Remove the decorations from the tub of water. Allow them to cool completely before placing them back in the tank.

* WARNING

Don’t use boiling water to clean plants, branches, or other decor that uses adhesive. Some of these decorations include plants with stone bases and molded Manzanita branches.

The boiling water warps the adhesive and ruins the structure. *

Use White Vinegar

Besides plain water, white vinegar is the most gentle method of cleaning decorations.

Vinegar is useful for cleaning hard water buildup and soft algal growth. It is rarely strong enough to handle hard algae.

Vinegar is a weak cleaning solution. It usually takes longer to break down deposits and algae than the others.

Here’s How To Use A Vinegar Solution:

1. Create a solution of 50% freshwater and 50% vinegar in a bucket or container.
2. Place the decorations in the solution so they’re entirely covered.
3. Allow the decorations to soak for about 3-6 hours.
4. Use a brush or algae sponge to scrub off any tough debris.
5. Remove the decorations and dump out the solution.
6. Rinse out the bucket and fill it with plain fresh water.
7. Add de-chlorinator to the container (follow the instructions to know how much to use). Mix.
8. Add the decorations to the container of dechlorinated water and allow it to soak for about 3-6 hours.
9. Remove the decorations and place them back in the aquarium.

Use Citric Acid

Citric acid is stronger than vinegar. It’s gentler than muriatic acid, hydrogen peroxide, or bleach.

It is safe to use a citric acid solution on all non-living decorations. It won’t strip the color off of decorations as long as it’s used in a concentrated solution.

Citric acid works faster than vinegar. It’s stronger and is better at removing tough algae buildup.

Citric acid is rarely enough for removing particularly tough algae. Extra scrubbing with algae brushes may be necessary.

Here’s How To Use A Citric Acid Solution:

1. Create a solution of 6 oz (about ¾ cup) of citric acid for every 1 gallon of freshwater. Create the solution in the bucket or container you’ll use for cleaning.
2. Place the decorations in the solution so they’re entirely covered.
3. Allow the decorations to soak for about 3-6 hours.
4. Use a brush or algae sponge to scrub off any tough debris.
5. Remove the decorations and dump out the solution.
6. Rinse out the bucket and fill it with plain fresh water.
7. Add de-chlorinator to the container (follow the instructions to know how much to use). Mix.
8. Add the decorations to the container of dechlorinated water and allow it to soak for about 3-6 hours.
9. Remove the decorations and place them back in the aquarium.

Use Muriatic Acid & Baking Soda

Muriatic acid also goes by the name “hydrochloric acid.” It is a strong, corrosive acid with a distinct, pungent smell. A muriatic acid solution is only safe for use with molded stones.

Muriatic acid is more potent than vinegar and citric acid. It easily strips algae and other waste from decorations.

Muriatic acid is much quicker than vinegar and citric acid. It often works on tough algae buildup.

The downside to this acid is that it is unsafe with all decorations and can strip colors over time. It is toxic to fish and invertebrates — always de-chlorinate the decorations after cleaning.

Here’s How To Create A Muriatic Acid & Baking Soda Solution:

1. Create a solution of 4 tsp. of muriatic acid for every 2 gallons of freshwater. The result is a dilute 5% solution.
2. Create the solution in the bucket or container you’ll use for cleaning.
3. Place the decorations in the solution so they’re entirely covered.
4. Allow the decorations to soak for 15-30 minutes.
5. Use a brush or algae sponge to scrub off any tough debris.
6. Add a few tbsp. of baking soda to neutralize the solution.
7. Remove the decorations and dump out the solution.
8. Rinse out the bucket and fill it with plain fresh water.
9. Add de-chlorinator to the container (follow the instructions to know how much to use). Mix.
10. Add the decorations to the container of dechlorinated water. Allow it to soak for about 30 minutes.
11. Remove the decorations and place them back in the aquarium.

Use Bleach

Bleach is tricky because it’s the most harsh method of cleaning decorations.

Bleach is often necessary for hard green algae when other solutions aren’t working.

Keep in mind that bleach solutions may cause discoloration in some decorations. Most decorations look nicer without the ugly algae, even with some discoloration.

Only use plain bleach to clean aquarium decorations. The product should comprise sodium hypochlorite and nothing else. Additives can be dangerous.

Here’s how to create a bleach solution:

1. Create a solution of ¼ cup of bleach for every five gallons of water. Create the solution in the bucket or container you’ll use for cleaning.
   1. NEVER mix bleach with any other chemicals; it is hazardous.
2. Place the decorations in the solution so they’re entirely covered.
3. Allow the decorations to soak for about 30 minutes.
   1. Soak them for longer if some debris is still stuck on the decor.
4. Don’t soak the decorations too long — the longer they soak, the more color they lose.
5. Use a brush or algae sponge to scrub off any tough debris.
6. Remove the decorations and dump out the solution.
7. Rinse out the bucket and fill it with plain fresh water.
8. Add de-chlorinator to the container (follow the instructions to know how much to use). Mix.
9. Add the decorations to the container of dechlorinated water and allow it to soak for about 3-6 hours.
10. Remove the decorations and place them back in the aquarium.

Diluted bleach solutions are also safe for some saltwater decorations. Aquarists often use white, bleached seashells and corals for their saltwater tanks. Algae are too easy to see on these white decorations; a bleach solution can help clear it up.

DO NOT place live corals in a bleach solution.

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DON’T Clean Decorations With Soap

Never use soap to clean anything associated with the aquarium. Soap kills fish, even in small amounts. It’s hard to rinse off as it leaves a residue that can leach into the aquarium water.