The growth of algae Is the chief reason why aquarium owners give up their hobby. They can easily seem overpowering, and about 30,000 species of algae are known. Some of them can double their numbers in two hours if conditions are suitable. And there is no way of wiping out algae entirely in an aquarium without killing the plants at the same time. But if you follow the advice on the following pages you will have far better chances in your efforts at keeping the unwanted elements to a minimum.
First of all it is important to realise that there will always be algae in an aquarium, and they will always get out of control if conditions allow them to. Algae are small plants, and live largely on the same nutrients as aquarium plants. While aquarium plants draw their nutrients from the light and water as well as their roots, algae only live on light and nutrients in the water. So the main cause of algal growth is an incorrect balance in the water. Too many fish in relation to the plants is a frequent reason for the formation of excess phosphor and nitrogen, which promote the growth of algae. Even if the balance between plants and fish is correct, however, overfeeding must be avoided. In fact the algae benefit first and foremost from the food. Lastly, sunlight must be avoided altogether. Fluorescent light, e.g. from Philips TLD 93, 94 and 95 (TS 930, 940 and 950), encourages plant growth at the expense of the algae. Simply observing these simple rules will to a large extent help to prevent algae from spoiling the pleasure of a beautiful aquarium.
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The aquarium owner's five worst enemies
About 30,000 different species of algae are known. The great majority of them are so rare or microscopic, that they are never seen. If an aquarium is invaded by algae, they are almost always one of the five types described below.
Brush algae are red algae, but the name is misleading, since they are most familiar as blue-black threads up to 2 cm long, which grow from the tips and edges of leaves. Red algae are less dependent on light than green algae, because they are able to absorb certain organic nutrients from the water.
Green water is caused by microscopic single-celled plankton, which can reproduce so rapidly that the water appears green. These green algae require almost the same lighting and nutrient conditions as the aquarium plants.
Fuzz algae are green algae which form a furry light green layer of fine threads on stones and leaves. The threads grow up to 3 cm long, then snap off and often continue to live as freely floating threads.
Blue-green algae can absorb light like green algae as well as organic nutrients from the water like red algae. They often form tangled bluish green rafts without any visible structure, and smell of earth.
There are many different species in each of these categories, but they can be identified and kept down in very similar ways.
Thread algae are green algae which form colonies of long threads between the plants. Large colonies can be removed with a rough surfaced flower stick.
(J) Photo: Jan Ole Pedersen (B) Photo: Claus Christensen Illustration: Salvinia natans (011)
The aquarium owner's most useful weapons
Algae are a pest, and therefore several chemical remedies have been produced, with promises of good results. Often, however, they damage the plants as much as the algae, and do not remove the cause of algal growth, so the pest is certain to attack again. The only reliable method is the patient use of natural, biological remedies. Here you can see what remedies are available, but you will have to try them out to find the right combination.
Large quantities of fast-growing plants, e.g. Hygrophila, Egeria densa, Vallisneria and Echinodorus bleherae (bleheri) take the nutrients from the algae. Ceratophyllum give off a substance which inhibits the growth of algae. Floating plants like Riccia are useful when light is the cause of algal growth. Adding CO2 promotes the growth of the plants at the expense of the algae. Make sure there is a good balance of fish and plants and avoid overfeeding. Keep fish that eat algae such as Crossocheilus siamensis, Octoinclus affinis and Poecilla, if possible together with Japonica-shrimps and Apple-snails.
Replace 50% of the water each week if you have trouble with algae, and avoid using a bottom filter or at least ensure that the flow rate is slow, so that the bottom filter does not stir up the nutrients in the water. Light up the aquarium for a maximum of 12 hours a day. Longer than this will not benefit the plants but encourages algal growth. Avoid sunlight altogether. Just half an hour each day is enough to make the algae grow uncontrollably. Always remove as much as possible of the algal growth by hand, and cut badly attacked leaves away completely. Always bear in mind that even a very slight change in the aquarium may tip the balance in favour of the algae, and you have to try all over again. That is part of the challenge of your hobby.
Caridina japonica and Crossocheilus siamensis - photos: Jan Ole Pedersen
DID YOU KNOW: From dream to reality - faster than you think
Going from a dream to reality need not take very long. To start off right find out which conditions you can offer the plants in your aquarium regarding such factors as lighting, CO2 and fertilizer. Then find the necessary information on the plants you want before buying them - ask your Tropica distributor or find advice on our web site. With the right advice, the path from dream to reality is no great distance.
Photos: Oliver Knott
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The word aquarium originates from the ancient Latin language, aqua meaning water and the suffix rium meaning place or building. Aquariums are beautiful and look good anywhere! Home aquariums are becoming more and more popular, it is a hobby that many people are flocking too and fish shops are on the rise. Fish are generally easy to keep although do they need quite a bit of attention. Puppies and kittens were the typical pet but now fish are becoming more and more frequent in house holds. In recent years fish shops have noticed a great increase in the rise of people wanting to purchase aquariums and fish, the boom has been great for local shops as the fish industry hasnt been such a great industry before now.