How to Clean Algae Off Fish Tank Decorations

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You put a lot of time, effort, and money into your aquarium to make it pleasing to look at and enjoyable for your fish, so you may be dismayed to see green or brown algae on aquarium decorations. Don't despair; it happens to even the most careful aquarium owners, and fortunately, getting rid of the algae is not too difficult using either hot water or a weak vinegar or bleach solution along with scrubbing.


Fortunately, getting rid of the algae is not too difficult.
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Cleaning algae on aquarium decorations

Cleaning an aquarium is best done while the fish are still in the tank. The risks to the fish are too great when moving them, balancing the pH of the water again, and disturbing the beneficial bacteria in the water. It is important, however, that you do not use soaps or chemicals when cleaning. Rest assured that aquarists have had great success getting rid of algae without using harsh materials that are detrimental to the health of your fish.


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Using boiling water to clean algae

Put a pot of water to boil on the stove and once it reaches a full rolling boil, continue to boil the water for three minutes. Then, remove it from the heat to cool a bit. Immersing plastic decorations into boiling hot water may damage, discolor, or melt them, so wait until the water is not quite as hot.


Meanwhile, gently remove one-quarter to one-half of the decorations from the tank. Taking them all out at once will cause too much disturbance in the tank, scaring your fish and stirring up everything, including any good bacteria the tank and substrate may hold. If the water has cooled some, place the decorations in the pot so that they are totally covered by water. Allow them to stay in the hot water for about 15 minutes and then rinse the decorations in warm tap water.


Clean aquarium algae with soft toothbrush

While the hot water will loosen the algae enough for much of it to be rinsed away, none of the methods for cleaning algae on aquarium decorations will remove all of it. Typically, some stubborn algae spots will remain. Use a soft toothbrush to lightly scrub these spots without hurting your delicate decorations. Rinse the scrubbed area with warm tap water and check for algae again, repeating the scrubbing as necessary. Be sure to insert the bristles into cracks and crevices where algae may be hiding.


Using vinegar or bleach on aquarium

When algae doesn't come off with water and scrubbing, using diluted vinegar or bleach may work better. For a vinegar bath, be sure to use plain white vinegar in the proportion of 1 cup of vinegar per 1 gallon of water. Let the decorations soak in the vinegar/water solution for 15 to 20 minutes. Remove the decorations from the solution and rinse them under warm tap water, scrubbing as needed. Allow them to air dry before putting them back in the tank.


If your decorations are very dirty, you may want to use a bleach solution in the formula of 4 teaspoons of bleach per 2 gallons of water. Soak the decorations in the bleach solution for five minutes only. Rinse them and then soak them in a pot of water with a dechlorinator tablet added to remove any trace of the chlorine. Rinse them again and if possible, let them dry in the sun for 24 hours. When using bleach, wear rubber gloves to protect your skin and a face mask so you do not inhale fumes.


Helping your fish live longer

Ensuring that your aquarium is clean and free of harmful bacteria can keep fish healthier and prevent them from dying prematurely. For example, betta fish in an aquarium have an average life expectancy of three years, but those in the healthiest environments can live to be 4 or 5 years old or even older.



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