How to Get Rid of Algae

April 25th, 2007

I keep aquariums because I like fish. They're pretty, relaxing to watch and can display very interesting behaviors. I know this might be difficult for some of you to believe because, well, you can't see your fish. When you look into your tank, all you see is a phlegm-like green canvas staring back at you. Either that or you see fish shaped silhouettes swimming around in what looks like 30 gallons of green Kool-Aid. Algae is a plague upon us all. It's everywhere. Chances are, there were already wind-blown algae spores in your tank when you bought it. Algae spores can sometimes even survive the treatment process by your local water purification system. The sad fact is you will never be rid of algae. That is unless you stop giving it the things it needs to live: water, nutrients, warmth and light. Which will also really frustrate your fish. Luckily algae is harmless, some would even say beneficial since it does take up harmful nitrites and nitrates from the water and give off oxygen as a byproduct. It's just…ugly. So let my experience as a pet shop boy help you. The number one question I was asked during my time at Pet Zone was "How do I get rid of algae?" and to tell you the truth, I'm pretty good at it.

Getting Rid of Algae

Don't overfeed the fish. Because, in essence, you will also be overfeeding the algae. Uneaten food equals extra nutrients in the water for the algae. Not only that, but if your fish are eating more, they are also creating more bodily waste which is a perfect fertilizer for algae.

Do regular water changes. While a good biological/ mechanical filter can significantly slow down the rate of nutrient accumulation in your aquarium or pond, it can't possibly take care of all of it. Without monthly water changes of about 30%, the rise in waste levels will lead to excessive algae.

Control the aquariums light exposure. Algae are photosynthetic organisms. They rely on light for all life processes. Make sure your aquarium is not placed in direct sunlight. Equally important is to turn the aquarium lights off at night. I suggest plugging the light fixture into a timer and setting it so that the lights are only on for 8-10 hours a day.

Scrub plants, decorations and turn over the gravel. When doing your monthly water change, take out any ornaments and plastic plants you think need cleaning. Scrub them off in the sink using nothing but hot water and your pretty little hands. If you need a little more abrasion, use a clean rag (make sure there's no soap residue of any kind) or an algae pad. And if the siphon you used for the water change didn't to a good enough job turning the gravel over, reach in and do it with your hand. That way the algae growing on the rocks will be buried, denied light, and die.

Use an Algae Pad for glass. Algae Pads are abrasive enough to remove algae but not so abrasive as to scratch up the glass. If you have an acrylic tank, make sure you use the Algae Pad specifically for them. Work the pad back and forth or in circular motions. Sometimes you have to apply a little force, but these work better than anything else I've tried. Just be very careful not to get gravel stuck between the Algae Pad and the side of the tank as this can scratch the hell out of it.

Getting rid of algae with algicides

For some reason you've lost control. Maybe you left town for a couple days and forgot the lights on. Maybe while you were gone your idiot brother, who you're paying well to look after the place, fed the fish 18 times a day because "They looked hungry." Regardless, algae got the best of you. Be it green algae, red algae or brown algae, it won. Or did it? Lucky for you there's numerous treatments on the market for aquarium algae. Most of which take care of many forms of freshwater algae including hair algae, string algae, algae blooms (green algae), blue green algae, blanket weed algae and black beard algae. The best I've found is called Algae Fix, or if that is not available, anything with polyethylene dichloride as the active ingredient. Just make sure to do a water change after you treat for freshwater algae so the dead stuff doesn't sit in the bottom of your tank and rot. If it's pond algae you're fighting and not fish tank algae, Algae Fix still has you covered. They have a product specifically for ponds that I would stake my mother's life on.

Algae Eaters

Algae Eaters are a fish keepers favorite way to take care of the green stuff. Here are just a few that can help out. Just be careful not to put too many in your tank. If there are too many algae eaters and not enough algae, they will starve.

Plecostomus – family Loricariidae – The classic algae eater. Many species available with some being much more effective than others. They help with glass, gravel and ornaments. I recommend the mountain stream (a.k.a. rubber) plecostomus for functionality. Royal or Leopard pleco for aesthetics.

Otocinclus – Otocinlus spp. -Great help for keeping small ornaments and plants clean.

Siamese Flying Fox - Crossocheilus siamensis- One of the few fish that eats thread algae (a.k.a. string algae, beard algae, hair algae).

Chinese Algae Eater - Gyrinocheilus aymonieri – A colder water species with a pretty good appetite for algae. Has a tendency to be a bit nippy.

Snails – Pick a snail, any snail. Almost all are good algae eaters. They also have a tendency to reproduce like guppies.

Algae Eating Shrimp – Caridina spp. – Great little critters. They will eat almost any type of algae. Should be kept in a very peaceful tank as many fish see them as food.

Live Plants. While they don't eat algae, they do stop algae from eating. Live plants compete with algae for the same nutrients.

Natural Alternatives

Barley Straw. When barley decomposes it releases humic acids. The reaction produced by humic acid, light and dissolved oxygen yields very low levels of hydrogen peroxide, which inhibits algae growth.

Ultra Sonic Waves. Ultrasonic sound devices transmit vibrations through the water that case the vacuoles inside algae cells to resonate and break. These units can be used in larger ponds as a chemical free and environmentally safe way to kill algae without harming your fish or plants. ultrasonic wave machine

UV Sterilization. Water can be pumped through a UV sterilizer to not only kill algae but some fish pathogens and parasites as well. These units mount easily on the side of the tank, the wall behind the tank or in the stand.

Salt. Salt can be used to kill pond algae at the ratio of 1lb non-iodized salt to 100 gals water. This works especially well for string algae. Dose three times with twelve hours in between. Be prepared to skim dead algae out of your pond so it doesn't rot and cause problems.