Aquarium Algae

Did you know that some types of algae can kill your fish? Well, it happens. But don’t worry! We have the answer to all those pesky problems and we are more than happy to share with anyone who asks us “What's up with my tank right now?"

There are all sorts of fish tank algae types - however, here are the most common culprits that can get out of control, some of the causes of them, and some easy cure for them.

  • Brown Algae
  • Green Hair Algae
  • Brush Algae
  • Blue Green Algae
  • Green Spot Algae

Get Your Free Report Today -

Top 3 Mistakes Newbies Make Setting Up Their Aquarium.


Aquarium AlgaeAquarium Algae

First let me suggest that whether you have a tropical or freshwater tank, your first step is to purchase an Aquarium Algae Scraper regardless. It will become a handy tool to expedite any problems quickly. It is a magnetic device that allow you to easily remove the algae in a fish tank, without having to get your hands wet.  My favorite is the Marina Magnetic Algae Scrubber.

How To Clean Algae From An Aquarium

Tropical Tank Health

Goldfish TanksGoldfish Tanks

The type of fish you have in your tank, will always be a factor of algae problems. For instance, the Goldfish produce lots of waste, which is lots of phosphates and nitrates, which when mixed with sunlight, creates fish tank algae. This is also the type of algae that will kill your other fish and plants.

Another example with the Goldfish (and some other species) is they will actually kill themselves over-eating (producing all the waste), and what they don't eat falls to the bottom to rot in the substrate. 

Over feeding creates waste, and leads to not only algae, but bacteria and illnesses for your fish.

There may be too much or too little light, or sunlight for the tank you have, so consider using a timer for your aquarium lighting and fish needs. Using aquarium light for more than six hours a day can cause excessive algae growth. Learn more about Tank lighting here.

Your PH levels are not appropriate for the acidity or alkalinity of the salt water or fresh water tank you have. 

If your Water quality is beyond help, I suggest changing at least 10% of it every week for a while, then on a monthly basis until your tank matures.

Learn more about Tropical Tank Health here.

Angel fishAngel Fish

The other side of the coin is the Angel fish who loves to eat, and thrives on vegetation. It not only filters and cleans the tank water of decomposed materials, it reduces aquarium algae. Learn more about the Amazing Angel Fish here.

Nerite Snails

Nerite SnailNerite Snail

Nerite snails are a popular and useful aquarium creature that helps to clean up algae.

It does this by eating hair-like projections on other aquatic organisms, as well as removing dirt from glass surfaces with its rough shell texture which can create scratches if touched too roughly by human hands or fingers while cleaning the tank!

They also keep your substrate in good condition so it's not too dirty looking after long periods without maintenance from you - all at no cost whatsoever!

Common Characteristics of Aquarium Algae

Brown Algae

    The most common type of algae found in aquariums is brown algae. It may first appear as a fluffy or spotty appearance on glass, rocks, substrate, plant leaves, and decorations. Brown algae grows more rapidly in low light. If brown algae happens in a well established tank, check all water conditions, and lighting again. 

    Possible Causes and Solutions:

  • Low light - replace old light bulbs.
  • High nitrates or phosphate levels - replace with a new filter and clean it often.

  • Poor water quality - conduct regular water changes.

How to Remove Brown Algae From Your Tank

The trick here is to use a small squeegee, and wipe with a single smooth motion, from top to bottom of the fish tank. By doing this you are scooping so that as little brown algae can float off into your tank's water with no problem at all.

Green Hair Algae

Another common type is green Hair algae. It can look bushy, with or without spots, and grow in clumps. It is light green, and can grow to over an inch long if left unchecked.

Possible Causes and Solutions:

  • High light - reduce lighting or time of it.

  • Low c02 - increase c02 levels.
  • Low nitrates - increase nitrate levels.

How to Remove Green Hair Algae From Your Tank

Use a good quality algae remover, and be prepared to use plenty of elbow grease to remove the green stuff from the aquarium glass.

Brush Algae (Black or Red)

You will find brush algae growing on the edges of the leaves, bog wood, around your filters, and usually in clumps of black or red tufts. leaf edges of slow growing plants, bog wood and around filters etc. This algae grows in clumps or patches of fine black or red tufts up to about 5 millimetres long.

Possible Causes and Solutions:

  • Low or fluctuating frequently CO2 levels-Increase the levels of CO2 levels for your tank. Increase water circulation and especially around the plants.

  • Low light tanks need to reduce water changes to see if this helps.

How to Remove Brush Algae From Your Tank

One of the easiest way to remove brush algae is to introduce black molly fish, or bristle-nose pleco into your aquarium.

Blue Green Algae

Blue green algae is not a real algae at all, but a bacteria. It will cover everything with a blue-green sheet of smelly slime. It can be peeled off, but grows back rapidly.

Possible Causes and Solutions:

  • Low nitrates or high levels of other nutrients - Improve the water quality and circulation. Stir the water to loosen the substrate and mix up the water. Improving water circulation reduces this algae.

  • Dirty substrates and filters - clean or buy new substrates and a new filter. Vacuum the substrate at every water change.

  • Too much light - do a 'black out' and cover the tank for a week or so.

  • As a last resort you can use erythromycin. However this will also kill the good bacteria, so please use with care.

Green Spot Algae

Forms hard green circular spots on the glass and plant leaves.

Possible Causes and Solutions:

  • Low c02 - check CO2 levels

  • Low p04 levels (phosphate) - Check P04 levels, and make sure you are not overfeeding.

  • Too much light - reduce time light is on between 8-12 hours. Using a timer is a great help.


Depending on the type of aquarium algae you have a problem with, will also determine how you can effectively treat it. But remember, Algae scrapers are great to remove any traces of algae.

Do you have specific issues or problems with your aquarium?  Ask here, and we will help you!


Buy The Which Fish Tank E-Book Today for $2


Buy The Which Fish Tank Big E-book Today for $7

I enjoy feedback on the content from my site's visitors ... so why not join and have your say .... please send your message to us by clicking the  contact us  link.

 Thank you so much.