Green water

Why has my pond turned green, and what can I do about it?

Green water in ponds is caused by a population of millions of microscopic algal cells which blooms in very favourable conditions. The combination of warm and sunny weather and high levels of nutrients in the water (phosphates & nitrates) causes the algae to grow out of control. Green water is not bad for fish, in fact it is a real tonic to their health. However, it’s unsightly nature makes it a common nuisance in ponds.

Effective Treatment?

Green water can be left to bloom for a week or so and it should decline, especially if the pond is planted with competitive plants such as lilies and submerged oxygenators. A clear pond can be guaranteed by installing an Ultra-Violet Clarifier to accompany a pump and filter system. This method is very fish friendly and will maintain clear water throughout the season. A Treatment such as Goodbye Green Water should be used and repeat treatments are usually required. Goodbye Green Water is a living biological solution for blanket weed it is 100 % natural with a unique blend of bacteria enzymes and activated barley straw.

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Blanketweed

My pond water is clear, but it is full of strands and tufts of hair-like algae. What is it?

If pond water is clear, especially where ponds are fitted with a UV, then blanketweed can proliferate in the sun-lit and nutrient-rich pond water. Blanketweed growth rates can be quite staggering, and this problematic pond infestation can be controlled in a number of ways.

1. A Treatment such as Goodbye Blanket Weed should be used and repeat treatments are usually required. Goodbye Blanket Weed is a living biological solution for blanket weed it is 100 % natural with a unique blend of bacteria enzymes and activated barley straw.

2. Nutrient-removing treatments can be added to the pond water to lock up the phosphates which fuel algae growth. Both methods should be accompanied by the manual removal of as much blanketweed as possible.

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Maturing a New Pond

I have installed a small pond and would like to add all the fish I can have as soon as possible. I have heard that a new pond needs ‘running in’. What does this mean?

A new pond is a lifeless, almost sterile environment. It will not support fish long term and if fish are added too quickly, then water quality and fish health problems will soon arise. A pond must be fitted with a pump and filter which are run continuously. The filter will become a living water treatment works that breaks down the toxic waste (ammonia) released by fish. Beneficial bacteria colonise the filter over many weeks, gradually building up to the level which will support your pond’s population of fish. For this reason, the pond should be stocked gradually over the first few weeks and months to allow the filter to mature and keep pace with the amounts of waste released by your fish. If too many fish are added too soon, then the water will turn toxic and lead to fish health problems. There are no short cuts to maturing a new pond and filter system.

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Filtration

I have been told that my pond needs a filter. I have seen so many filters that all look so different. What is a filter and why do I need one?

A filter in some respects is more important than the pond itself when considering the health of fish. It is your passport to trouble-free fishkeeping. A filter performs several complementary functions making the pond water suitable for fish. A filter is fed continuously with water from the pond and first removes any solid matter. The toxic ammonia excreted by fish is soluble and the beneficial bacteria in the filter work continually to break this material down into nitrites and finally less toxic nitrates. A filter takes many months to fully mature while the bacterial colonies become established and a pond should be stocked gradually to follow. A filter will require regular maintenance and when this is carried out, care should be taken not to disturb the whole filter as this will adversely affect the filter’s performance.

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Pond Volume

How can I calculate the volume of water in my pond?

It is essential that a pondkeeper knows the volume of their pond system (which includes the filter volume). If you are ever in the position of having to treat your pond against algae or disease then the dose is calculated on the pond’s volume. You could use our pond calculator on the UK homepage or.

To work out the volume in: A: Gallons: Length x Width x Depth (in feet) x 6.25 = Volume in gallons B: Litres: Volume in Gallons x 4.55 = Volume in litres.

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Fish Health & Disease

What are the implications of the health and disease of fish to a pond keeper?

The prevention of disease is achieved by providing your fish with a stable, healthy pond environment and a complete and balanced diet. However, pond fish are like any other animal in that they can develop health problems. These will manifest themselves as a change in behaviour (sulking, flicking, scratching, loss of appetite, gasping etc) or through specific disease symptoms (spots, ulcers, ragged fins etc). If your fish appear to develop a problem, try to identify the cause immediately. Poor water quality is the cause of most fish problems and the water should be tested to determine whether any parameters are outside their desirable limits. If they are, then address the problem and treat the disease. If the disease symptoms are treated but the cause is not addressed then the fish are not likely to recover. Most fish diseases can be treated satisfactorily using the most appropriate treatment . They are added according to the volume of your pond system. Your local aquatic shop should be able to help you with precise diagnosis and treatment advice. But don’t take long to act as you are in a race against time.

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Feeding Fish

What are the guidelines for feeding pond fish?

Feeding time is probably the most enjoyable activity of keeping fish. It is an important time to check on the health of your fish by inspecting fish close at hand and observing their behaviour. If possible, pond fish should be fed on a basis of a little and often rather than one main feed a day. On each occasion, they should be fed what they will eat in 3-5 minutes, removing what they haven’t eaten from the surface. Subsequent feeds should be adjusted accordingly. Overfeeding will lead to water quality problems as the excess food soon pollutes the pond water. In the warmer summer months, fish will have larger appetites and consume larger quantities of food than any other time of the year. At these times, a higher protein "growth " diet should be offered and at cooler times, in spring and autumn, a lower protein "wheatgerm" food will prove to be better for your fish and filter.

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Water Quality

I am considering keeping fish in a garden pond. I have heard pond keeping friends discuss water quality more than their fish. What is meant by ‘water quality’ and why is it so important?

Understanding water quality is the key to successful fishkeeping. Fish have specific requirements and tolerances of their environment and if they are not provided, they will become stressed and suffer health problems. Water quality covers a number of measurable characteristics of water such as temperature, pH (how acid/alkaline the water is), ammonia, nitrite and nitrate (measures of water pollution). A pond should be managed to maintain a stable water quality within the desirable limits. This can best be achieved by providing as large a pond as possible and by using an adequate filter system and stocking wisely. A partial water change should be carried out fortnightly to freshen up the pond and dilute the build up of certain persistent pollutants. Know water quality, no fish health problems.

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Testing Water

I believe that a pond keeper should test their pond water. Why do I have to test the water and what do I test for?

Healthy water quality is the secret to successful fishkeeping. Testing water is the most accurate way of determining the suitability of pond water for fish. Test kits are available in a number of different forms. They are easy to use and give a quick and accurate indication as to the state of your pond environment. Pond water must be tested regularly during the weeks and months over which a new pond is matured and stocked with fish. The tests will determine whether your filter is keeping pace with the waste produced by the fish and food in the pond. Several tests to use are:

1. pH – Checks the acidity/alkalinity of pond water. It should be in the range of 7.5 - 9.0 (max), with 8.0 - 8.5 being the most desirable. If the pH is outside this range then remedial action should be taken.

2. Ammonia. This is a test for the amount of raw, soluble waste present in the pond. It should be broken down by a biofilter at the same rate at which it is produced, giving a zero reading. A positive ammonia reading indicates the water is toxic to fish and should be diluted with a partial water change. Feeding should be stopped and only recommenced when a zero reading is achieved.

3. Nitrite. Bacteria in a filter break down ammonia into nitrites which are still toxic to fish and quite a bit more persistent in the water than ammonia. Again, a zero reading is essential with the same action carried out as for a positive ammonia reading.

4. Nitrate is the ‘bank’ where all nitrogen from ammonia and nitrite is eventually deposited. It is only harmful in excessive concentrations and can be removed through plant growth or a fortnightly/monthly partial water change.

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How many Fish?

How many fish can I stock in my pond?

The stocking of a new pond should be gradual to allow the biofilter to keep pace and mature with the fish. The pond area is the single most influential factor when calculating the amount of fish that may be stocked. The pond, when fully mature should be able to sustain 3” of fish per square foot of clear water area, possibly rising with adequate filtration, aeration and water turnover.

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Can I Keep Koi in My Pond?

What is so special about koi that makes them only suitable for purpose-built ponds?

Koi are specially selected ornamental carp that are found in an array of colours, patterns and varieties. They can become very tame and make a highly desirable addition to a pond. Koi are more susceptible than other pond fish to developing diseases or health problems so a suitable pond environment must be provided. A purpose-built pond is not entirely necessary to keep koi, but they have particular requirements which larger ponds will accommodate more effectively. 1. Deep ponds (min. 3 feet) with open swimming space. Koi can grow up to 3 feet in length and require the space and depth in which to swim. A deep pond also helps to keep the water quality more stable which helps this very fragile fish. 2. A suitable filter that will handle the amount of waste produced by such voracious feeders.

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