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How do I control Algae in my Goldfish Aquarium?

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How do I control Algae in my Goldfish Aquarium?

Here’s how without using harsh chemicals!

A little algae in your goldfish aquarium can actually be a benefit. Goldfish thrive on good green algae. Goldfish will graze on algae just like a cow grazes on grass. Plus, it works great as a laxative to help prevent your goldfish from becoming constipated, which causes them to float upside down at the top of your goldfish aquarium. Another benefit is, it really helps to keep your goldfish aquarium water free from excess nutrients while providing some oxygen. One of the most successful tropical show fish breeders in the country kept his fish in aquariums full of mixed green and brown algae and raised his fry in “pea green” water.

When trying to control algae, pay special attention to  water quality and the health of your goldfish

You never want to remove all the algae from your goldfish aquarium. Healthy algae growth is a sign of a healthy goldfish aquarium!

Algae acts like a “canary in a mine”. Years ago Miners would take a caged canary with them into the mines. When the canary fell off it’s perch, the Miners ran fast from the mine because of the presence of toxic gasses in the mine. The gasses in the mine would kill the canary before the miners. That’s how algae works! If you see your algae dying, you have a water problem and your goldfish will be next!


DO NOT USE CHEMICALS TO REMOVE ALGAE FROM YOUR GOLDFISH AQUARIUM. Anything that kills algae is very stressful on your goldfish.

Controlling Nuisance Algae Growth

Nuisance algae growth is a symptom of  a series of water quality problems

No one wants a goldfish aquarium so overrun with algae or “pea green” water that they can’t enjoy watching their goldfish.

Here are some of causes of Nuisance Algae Growth:

1- Overfeeding:

  • Overfeeding your goldfish is a very common cause of excessive algae growth

  •   Overfeeding causes a rise in phosphate levels, algae’s favorite food!

  •   Overfeeding causes other problems also, left over goldfish food can cause serious water problems, including high levels of ammonia and nitrite, as well as low oxygen and pH levels  

Feeding Tips:

  • A healthy goldfish is a goldfish that’s always a little hungry. It’s healthier to have your goldfish looking for food and grazing on algae than sitting on their fat bellies waiting for you to overfeed them

  • Feed only what your goldfish can eat in two to three minutes. If your goldfish don’t clean up ALL their food within 2 to 3 minutes, you’re feeding too much

  • Never leave any food on the bottom of your goldfish aquarium

  • If you’re having an algae problem, cut back feeding to just once a day

In fact, feeding your goldfish just once a day, with a small snack of a good “green” food like our Spirulina or Salad Supreme makes a great diet

2- Nutrients (Algae Food!!):   Where do they come from?

·         Two of the most common causes of nutrients in your goldfish aquarium come from decaying food and fish waste

·         Phosphate is steroids for algae!! Algae LOVES phosphate!! If you’re having a major algae problem test your water for goldfish aquarium phosphate

·         IMPORTANT: If your phosphate level is high, check your TAP WATER. Some “city water” and “well water” contain phosphate, nitrogen compounds such as ammonia, nitrite, nitrate

·         A 25% water change once a week will help to remove or dilute nutrients in your goldfish aquarium, but if these nutrients are present in your tap water, you’re  fighting a losing battle

·         There are phosphate removers on the market

3- Aquarium Lights & Sunlight:

  • Never place your goldfish aquarium in direct sunlight. Sunlight encourages algae growth, plus, it can raise the temperature in your goldfish aquarium to dangerous levels

  • Goldfish aquarium lights should be limited to 8 to 10 hours a day to help control algae

4- Oxygen: Algae Hates Oxygen and thrives on Carbon Dioxide!!

  • Good Aeration is critical in controlling algae in your goldfish aquarium.

  • Goldfish Connection’s diffusers bring the deadly algae causing carbon dioxide from the bottom of your goldfish aquarium to the top, releasing it from the water and then oxygen is introduced. Reducing carbon dioxide reduces algae growth.

Goldfish Connection’s 25 Watt U.V. (for large tanks 55 gallons and up) and Clarifier Excel (for tanks up to 40 gallons) will clear green water and reduce free floating algae from multiplying .  

Any one of these water quality issues alone may not solve your algae problem however; if you practice them all you will see excellent results.

Thanks for your time,


XX - 05/25/09 - Viewed 61232 times.

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