brown algae

How To Remove Algae From Fish Tank Decorations

In Aquariumsby PaulK


The fastest way to remove algae from a fish tank decoration is to remove the decoration, spray hydrogen peroxide on it and let it sit for 5 minutes, brush it off with a sink scrubber or fish tank scrubber, rinse and return it to the fish tank. Make sure to use a water conditioner in your fish tank after returning the decoration. That should take care of the algae.

How Do You Remove Algae From Aquarium Plants?

If you have plastic or silk aquarium plants, you can use bleach. Heat up a pot of water to almost boiling, put in a ½ cup of bleach and reduce the heat to simmer. Put in the plastic plants and swish them around for a while. Rinse the plants in a bucket of cold water until the bleach smell is gone. If the smell isn’t gone yet, let them soak for about 5 minutes or so. Rinse under a faucet and return them to the tank. Always use water conditioner in your fish tank after using tap water.

How Do I Stop Algae In My Fish Tank?

If you balance the nutrients, nitrates, and light in your fish tank, you shouldn’t have too much of an algae problem. Algae feed off of nitrates, phosphates and lots of light. If you have live plants, make sure they are healthy, so that they will outcompete the algae for food and nutrients. Limit your lighting to 6-8 hours. Consider getting a phosphate remover like this Seachem Phosguard on Amazon.

Certain types of fish, snails, and shrimp feed off of certain kinds of algae, so think about adding some to your tank. Here are some snails to consider for clean-up duty.

Get a UV sterilizer to inhibit the growth of algae from stage 1 to stage 2.

If you don’t have live plants or bacteria and the level of nitrates spikes, you will have to do frequent water changes.

How Do I Get Rid of Green Algae in My Fish Tank?

Green dust algae form on the glass and have a dusty appearance. You can remove this with a magnetic algae scraper. Let the algae run its course for 3 weeks or so, then scrape it off and do a large water change.

Green spot algae can form hard, green spots on the glass and broadleaf plants. Low phosphate, CO2 levels, and poor water circulation are generally the cause. Increase phosphate levels by adding monobasic potassium phosphate. You can scrape this off the glass with a razor blade or magnetic fish tank scraper. Bristlenose Pleco fish are great for eating this type of algae.

Green water is a one cell algae that turn your fish tank water green. Excess ammonia is usually the cause of this. Since they are single-cell algae, they grow quite rapidly.

UV sterilizers are the best way to fix this or try this Ultralife blue-green slime remover from Amazon. Here is a video on how the UV sterilizer works.

How To Remove Algae From Aquarium Rocks

Same treatment as removing algae from decorations. Pull out the rocks and spray with Hydrogen Peroxide which kills the algae on contact. Wait five minutes, wipe them down and return to the tank. Another way is to lay them out in the sun for a few days, which also kills the algae.

If you don’t want to keep cleaning the algae in your fish tank all of the time, you need to find ways to at least manage the algae growth. You should understand where algae come from and what causes algae to grow out of control.

Root Causes of Algae Growth

If your aquarium has too much ammonia from lack of proper filtration, too many fish or overfeeding the fish, algae will feed off the ammonia. You also need healthy, live plants to out-compete the algae for nutrients, limiting their growth. That means plenty of nutrients for your plants so they will grow. Too much lighting will also promote algae growth. Here are my top 5 aquarium plants for beginners.

Ways To Control Algae in Your Aquarium

  • Adding certain fish, shrimp, or snails, known as the “clean up crew”, will help to control your algae.
  • Limit the amount of light on the tank to 6-8 hours. Also, change the fluorescent tube lighting if it’s more than a year old. Tube lights lose their spectrum after some time, which is good for algae growth.
  • Use a UV Sterilizer. Great for green clearing green algae.
  • Make sure you have good water circulation.
  • Make sure your live plants are healthy.
  • Don’t overcrowd your fish tank and don’t overfeed the fish.
  • Use Seachem Excel for boosting CO2.

You will never be totally algae free, but there are ways to manage it so you don’t see it. There are many types of algae, so it’s important to understand the different types and how to combat them for a cleaner fish tank.

blackbeard algae

Blackbeard Algae

Black beard algae grow on leaf edges of slow-growing plants, bogwood and mechanical equipment. It grows in clumps or patches of fine black tufts up 0.5 cm. The cause is usually low CO2 levels and/or poor water circulation. Siamese algae eaters are known to eat this type of algae. You can also use Seachem Excel to treat it.

blue-green algae

Blue Green Algae

Blue-green algae is not really an alga but a bacteria that use photosynthesis. It covers everything in a blue or green slimy mat. You can easily peel it off, but it will grow back very quickly. It is very common to find this growing on the substrate and the front of the glass tank. The growth is usually caused by low nitrates, dirty substrate or dirty filter. To fix this, clean out as much of the algae as possible, do a 50% water change and total blackout of the tank for 4-5 days. Cover the tank so no light gets in.



Cladophora or blanket weed as it’s known is a branching green type of algae usually cause by low CO2 and nutrient levels. You will have to raise CO2 levels and manually pull them out. They can be stubborn to get rid of.

brown algae

Brown Algae

Brown algae form brown patches on plants and tank glass. High ammonia in the tank is usually the cause. That’s why you’ll see it in newer tanks before the filter has had a chance to grow bacteria. This can be vacuumed out and wiped off with a soft cloth.

Hair algae look like fine hair that grow on plants. Causes could be low CO2 levels, low nutrient levels or ammonia spikes. Amano shrimp, Rosy Barbs, and Mollies eat this type of algae.


Rhizoclonium Algae

Rhizoclonium algae look like puffy balls of fine strands that grow on plants and substrate. Overdose with Seachem Excel. Amano shrimp will eat this type of algae.

Staghorn algae grow in strands that branch out and look like a deer antler. It is black to grey in color and sometimes has a red tint. Causes are low CO2, poor water circulation, dirty filtration, and not doing water changes after gravel cleaning. Reduce feeding of fish, vacuum the substrate and do a water change. Try overdosing Seachem Excel.

Staghorn Algae

Algae Eating Fish

Siamese Algae Eaters – Probably one of the most if not the most effective algae eaters out there. They will eat most types of algae and other food waste. They only grow to about 2 inches in length, so they can be kept in most any tank. They are a hardy fish and easy to care for. You can mix them with other species of fish with no problem. They do become territorial if kept with too many of their own kind, so keep numbers to 3-5 per tank.

Bristlenose Pleco – A good algae eating fish for larger tanks. Their sucker mouths cover a lot of ground. They can grow up to 6 inches and are night feeders. The best part about the Bristlenose Pleco is that they will eat green spot algae, which most of the others will not touch. They will get along with most other fish species as well.

Otocinclus Catfish – Also known as ‘dwarf suckers.’ Very small in size, but can eat a lot of algae. Their small size allows them to get into tiny crevices and consume algae. They prefer brown, and soft green algae.

Florida Flag Fish – Only eat algae if there is not enough food.

Mollies – Only eat algae if there is not enough food.

African Cichlids – Primarily eat green algae

Algae Eating Snails

Zebra Nerite – One of the most popular types of eating snails probably because of their beautiful zebra-like shell. Nerite snails also eat most every type of algae including the harder to eradicate green spot and green beard algae. They can be easy targets for predatory fish like cichlids, so be careful of the species of fish you add to the tank. They also like to climb out of the tank, so the tank must be well covered. They will also leave hundreds of small, white eggs around the tank which can look unsightly.

Ramshorn Snails – Great for tanks with lots of plants. They like to pick the algae off of plants, decorations, and tank walls.

Mystery Apple Snail – These grow pretty big like to the size of a baseball, so you need a pretty big tank for these guys. As you can imagine, they have a big appetite and will consume most types of algae. Make sure there is plenty to eat for them because they will start eating the plants if there is not enough food.

Malaysian Trumpet Snails – Good algae eaters. Small in size. Will not eat your plants.

Algae Eating Shrimp

Amano Shrimp – These shrimp are constantly hungry and will eat most types of algae except green spot algae and blue-green algae. They only grow to about two inches, so they are perfect for smaller tanks. They need to be kept with docile fish so they don’t become fish food.

Cherry Shrimp – Known for their bright red color you can find these at most pet stores. They are great at getting into small hard to reach places that algae eating fish can’t get at. Nice color to have in the tank too.

If you keep your tank maintained with filter cleanings, water changes, not too much light especially sunlight, healthy plants, and adding algae eaters, you shouldn’t have too much trouble with algae growth.

When it comes to algae in your fish tank, what is your single biggest challenge or frustration? Leave a comment below. is a participant in the Amazon Affiliate Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to

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