Instructions
Feed your goldfish once per day. Overfeeding fish is a common cause of algae growth because it makes phosphate levels rise, creating ideal conditions for algae to thrive. If you notice leftover food sinking to the bottom of the tank, that is a good indication you are overfeeding the goldfish.
Clean the goldfish tank on a regular basis. Algae thrive on nutrients, and nutrient levels rise when decaying food and waste are left on the bottom of the tank. If you have a large aquarium, do a 25 percent water change once per week to dilute the nutrients in the tank. Smaller tanks will benefit from a complete water change once per week.
Decrease the amount of sunlight the fish tank is exposed to. Sunlight encourages algae to grow, and fish tanks should never be kept in direct sunlight. If your fish tank has lights, limit the amount of light to eight to 10 hours per day.
How to Stop Algae Growth In Goldfish Tanks
Goldfish are inexpensive and easy to care for in home aquariums. One of the problems goldfish owners face, though, is controlling the amount of algae in the fish tank. Small amounts are beneficial to goldfish because algae is a source of oxygen and provides healthy nutrients to the fish. But an overabundance of algae can cause the goldfish tank to become cloudy and green.