Brown Algae Causes

Algae of any kind can be unsightly on a pretty aquarium, but brown algae can look downright disturbing. Brown algae forms for a variety of reasons, but it is most common in new tanks and in saltwater aquariums that contain only fish. If you're concerned for the health of your fish and the aesthetics of your aquarium because of a sudden increase in brown algae, you'll need to examine multiple aspects of your aquarium setup.

  1. Excess Feeding

    • If you put too much fish food into your aquarium, nutrients can build up and begin to grow algae instead of nourishing your fish. To avoid overfeeding, follow the feeding instructions on the package of fish food. If you only have one small fish, you will be using less food than if you have ten large fish. If you notice a buildup of brown algae, try using a bit less fish food and see whether that clears it up.

    Water

    • Brown algae often forms because of excess nutrients, but these don't always come from the food you're feeding your fish. They can also come from the water you use in your fish tank. Depending on your water source, you may have high levels of phosphate, chloramine, silicate, nitrate or phosphate. Purchase a water testing kit to determine whether these nutrients are present in your tank. If they are, you might try using a chemical filter. You can also try a phosphate absorbing resin.

    Aquarium Maintenance

    • Brown algae tends to grow in dim environments where it has an advantage over the light-loving green variety. Examine the light in your aquarium to see whether it has dimmed. Brown algae can also occur in tanks that are not cleaned regularly. Be sure to clean decorations within your tank as well. Also, change the water regularly and clean the gravel in your aquarium. And don't forget the filters.

    New Aquariums

    • Brown algae can be common in new aquariums. This is because conditions within the aquarium take time to stabilize. Nutrient levels may vary within the first few months of setting up your aquarium. For this reason, you should give your tank 2-12 weeks to stabilize before becoming too concerned about brown algae. During this time, simply be sure to keep your aquarium clean and well-lit.