Algal Problems...?
Algae in your tank or pond? It can turn your pristine aquascape into a horrible eye-sore in a matter of days. This change is a symptom of wider problems.
Excess algal growth is an indicator that there is nutrient excess (created either through overfeeding and/or accumulation through insufficient water changes) which can cause immune suppression in fish.
The presence of algae in your tank adds another complicated dynamic to balancing the tank environment. Algae produce oxygen through photosynthesis in daylight hours, but become net consumers of oxygen when the lights go out.
This can lead to a critical depression of tank oxygen levels - causing asphyxiation of your fish. Algae can pose further risks to your fish as some species can produce toxins which can damage their gills and impair their immune function.
Algal overgrowth can be generated through a variety of pathways. It could be from poor environmental conditions (too many fish in the tank, over feeding, infrequent water changes, excessive fertilising) or wrong lighting (too much or of the wrong spectrum).
The most common forms of algae can be described by their colours - green, blue-green, red, and yellow.
Algae are classified according to where they live:
phytoplankton (also known as planktonic algae) float freely in the water;
periphyton are attached to aquatic vegetation or other structures; and
benthic algae grow on the bottom or bottom sediments.
Recognising the type of algae provides an insight to the conditions that permitted their establishment. As such, different methods may be used to achieve effective eradication. It may be simple like changing water more frequently, using a suitable lighting type and period, decrease feeding or introducing more aquatic plants to altering the pH, water hardness, using anti-algal chemicals and installing a UV-clarifier. The combinations are enormous!
The fundamental ways of suppressing algae include:
Carry out very regular partial water changes (30% of tank volume) every 14 days.
Reduce the stocking density of your aquarium.
Don't over-feed - as a rule of thumb, fish's stomachs are approximately the size of their eye and so this is about as much as you should feed.
Use white daylight bulbs - lights that peak in the blue and red spectrum are best for photosynthesis and hence encourage plant as well as algae growth. So, by using plain white light, although it is not perfect for plants, it will help to hinder algae growth.
Decrease photoperiod - having light available for a shorter period will make it more difficult for algae to make their food and multiply.
If the tank receives sunlight, reposition the tank or shade it to avoid any direct sunlight. *Remember, it is dangerous to move a filled tank.
Add some water plants to your aquarium: aquatic plants will compete with the algae for nutrients and light.
Introduce an algae eating fish that is suitable for your set-up - examples would include bristlenose catfish, chinese algae eater.
You may wish to install a UV-clarifier or proceed with chemical or other biological treatment. *NOTE: chemicals should never be the sole treatment. They should be used only after or in conjunction with management strategies as outlined.
By Dr Richmond Loh - Last updated 16 November 2012
