Fish Leech/Piscola Geometra.
There cannot be many worse sights for the Koi keeper than to observe a leech having a meal at the expense of the well being of a favourite Koi. Then having to stand helpless beside the pond, resisting the temptation to net the fish and remove the parasite, knowing full well that more leeches lie in wait to attack as soon as the Koi is back in the water again. Leeches are harboured by objects in the pond, especially plants and their containers. In fact is the pond plant that can prove to be the source of the initial introduction of this pest to the Koi pond.
There are many organisms that resemble the Fish Leech, and some may indeed be members of the same family. Such organisms can be found in the pond itself usually around the plant life, or in the filtration system, and sometimes they occur in very large numbers. The size and colour of these wormlike organisms will vary with the species. but they are commonly grey, brown or even red. However unless you are seeing the organism actually attached to the body of the Koi themselves the you are not dealing with the Fish Leech.
Piscola Geometra is the most common we find in the garden pond, and therefore the main problem for the Koi keeper. It can clearly be seen firmly attached to the Koi under attack, its contractile can be seen expanding and retracting. The coloration of the body will vary according to what has been digested, if recently the parasite has enjoyed some fresh Koi blood the body will be a brownish colour, but it will be paler if the parasite has not eaten recently. Through the magnifying glass, or sometimes with larger specimen, Piscola Geometra can be observed to have a geometric body pattern, hence the name.
The health risks that pertain to all parasites that have the ability to damage the body or gills of fish apply to the Leech, the dangers of secondary infections, and the actual passing on of disease are always present. The Leech just like the Fish Louse feeds on blood, which adds to the risk of anaemia depending on the number of parasites involved. There are certain parasites that can carry and transmit specific conditions, and the Fish Leech is in that category, it is known to carry organisms that are found parasitising the blood and major organs of fish.
The greatest problem in eradicating Leeches from the Koi pond are the cocoons. These cocoons are what we would term eggs in other species, and they harbour the new generation of Leech, they do not resemble an egg being long, thin and rather dirty grey in colour. The cocoon cannot be permeated by certain chemicals, and that is why chemical control of the parasite is so difficult. The cocoon can take three months or more to hatch out, depending on temperature, which is a major influence. At the onset of a Leech infestation you will have no idea how many cocoon generations there are, or the variable times they will all hatch, and this adds further to the control problems.
Once the parasite is in residence in the Koi pond it has to be eradicated as soon as possible, it will only go on to breed out of control in the unnatural environment of the pond. The only alternative to chemical control is a total pond clean out, the pond and system being left to dry out for a few weeks.
Ensure all objects in the pond whether functional like the submersible pump or fountain, or ornamental such as rocks or statues, are well examined for cocoons are often found in the safe haven beneath such items. Discarding plants in ponds infested with Leeches is essential, lilies are beautiful but they are a common source of Leeches, try to buy them from a centre that can assure you the plants are not reared in fish lakes. Better still have your plants in a pond just for that purpose. Whilst many Koi keepers are not enthusiastic about plants in the Koi pond, as the Koi do tend to spoil them anyway, we have to remember that many fish keepers will always want some plant life in the pond. There is of course the argument that plants in the pond environment help to improve the water quality.
When the pond cleaning is complete the keeper will have learnt the hard way to identify the Leech cocoon. Being easy to spot it is not likely a Koi would be returned to the pond with Piscola Geometra attached, but do remember that the mouth and gills need to be checked, and any Koi that have been damaged by the Leech may need topical treatment with a bactericide.
Constant improvements in medication are made to eradicate this parasite, please contact us for treatments and correct use of dosage for your pond and Koi.
There are many organisms that resemble the Fish Leech, and some may indeed be members of the same family. Such organisms can be found in the pond itself usually around the plant life, or in the filtration system, and sometimes they occur in very large numbers. The size and colour of these wormlike organisms will vary with the species. but they are commonly grey, brown or even red. However unless you are seeing the organism actually attached to the body of the Koi themselves the you are not dealing with the Fish Leech.
Piscola Geometra is the most common we find in the garden pond, and therefore the main problem for the Koi keeper. It can clearly be seen firmly attached to the Koi under attack, its contractile can be seen expanding and retracting. The coloration of the body will vary according to what has been digested, if recently the parasite has enjoyed some fresh Koi blood the body will be a brownish colour, but it will be paler if the parasite has not eaten recently. Through the magnifying glass, or sometimes with larger specimen, Piscola Geometra can be observed to have a geometric body pattern, hence the name.
The health risks that pertain to all parasites that have the ability to damage the body or gills of fish apply to the Leech, the dangers of secondary infections, and the actual passing on of disease are always present. The Leech just like the Fish Louse feeds on blood, which adds to the risk of anaemia depending on the number of parasites involved. There are certain parasites that can carry and transmit specific conditions, and the Fish Leech is in that category, it is known to carry organisms that are found parasitising the blood and major organs of fish.
The greatest problem in eradicating Leeches from the Koi pond are the cocoons. These cocoons are what we would term eggs in other species, and they harbour the new generation of Leech, they do not resemble an egg being long, thin and rather dirty grey in colour. The cocoon cannot be permeated by certain chemicals, and that is why chemical control of the parasite is so difficult. The cocoon can take three months or more to hatch out, depending on temperature, which is a major influence. At the onset of a Leech infestation you will have no idea how many cocoon generations there are, or the variable times they will all hatch, and this adds further to the control problems.
Once the parasite is in residence in the Koi pond it has to be eradicated as soon as possible, it will only go on to breed out of control in the unnatural environment of the pond. The only alternative to chemical control is a total pond clean out, the pond and system being left to dry out for a few weeks.
Ensure all objects in the pond whether functional like the submersible pump or fountain, or ornamental such as rocks or statues, are well examined for cocoons are often found in the safe haven beneath such items. Discarding plants in ponds infested with Leeches is essential, lilies are beautiful but they are a common source of Leeches, try to buy them from a centre that can assure you the plants are not reared in fish lakes. Better still have your plants in a pond just for that purpose. Whilst many Koi keepers are not enthusiastic about plants in the Koi pond, as the Koi do tend to spoil them anyway, we have to remember that many fish keepers will always want some plant life in the pond. There is of course the argument that plants in the pond environment help to improve the water quality.
When the pond cleaning is complete the keeper will have learnt the hard way to identify the Leech cocoon. Being easy to spot it is not likely a Koi would be returned to the pond with Piscola Geometra attached, but do remember that the mouth and gills need to be checked, and any Koi that have been damaged by the Leech may need topical treatment with a bactericide.
Constant improvements in medication are made to eradicate this parasite, please contact us for treatments and correct use of dosage for your pond and Koi.