Argulus/Fish Louse
Image supplied by E.K.K member
There are few species among the relatives of Cyclops and Daphnia, which are a popular and natural food source for our fish, that constitutes a potential danger to our Koi.
Argulus, commonly known as the Fish Louse is one of the larger crustation parasites, usually 5-6mm or 1/4" in size but can be up to 10mm or 1/2" and is one of the few parasites that can be seen with the naked eye, sometimes resembling black spots. They are oval in shape, greeny brown in colour, semi transparent and have two disc shaped suckers on the underside of the body which are used to attach themselves to the fish. Argulus has four pairs of legs; these are used for swimming, not walking. The parasite clings to the body of the fish with numerous barbs, hooks, spines and suckers attached to its body and legs. You can imagine the damage the various appendages will do, but its most lethal weapon is its mouth.
Their survival depends on being able to feed on a plentiful supply of fish tissue and fluids. To achieve this need they have a very complex mouth arrangement. The mouth cavity contains the mandibles which equate to our jaws, in the centre is the stylet, the sole purpose of this is to inject a type of poison into the fish, this acts as an anti-coagulant to ensure the wound remains open for the next predator. Frequent feeding from the same area by other fish lice and casual agents eventually lead to lesions, ulcerations and is an open invitation to bacteria and fungal spores. If this parasite invades the gill severe damage may be caused resulting in breathing problems and possibly bacterial gill disease.
As Argulus is a free-swimming parasite it can easily transmit diseases from fish to fish within your pond. Frogs and Newts can be culprits for bringing this parasite into the pond; we can unwittingly do it ourselves by not inspecting a newly purchased fish once it has been bagged. Do not let the dealer tell you that your fish is nice and clean, check it yourself, particularly underneath. Adult fish lice are relatively easy to spot, juveniles are more difficult.
Aurgulus is an egg layer, the eggs are laid in thin sticky strips a few centimetres long so they will adhere to the bottom of the pond, or any convenient surface for safety. Fish Lice have a simple lifestyle in comparison with other crustation parasites such as the Anchor Worm, as many of the metamorphic stages take place in the egg. The complete lifecycle is influenced by a number of environmental factors; duration can be up to 100 days, this being largely dependent on temperature. Juveniles must find a host within a few days to survive whereas the adults can survive for as long as 15 days without a host. The female has the potential to lay approximately 1000 eggs so you can appreciate that this parasite is not to be taken lightly.
It is most unlikely that the numbers of Fish Lice will diminish naturally in the pond environment, almost certainly you will have to resort to the use of chemicals to eradicate them. The difficulty being is that you need to catch the full lifecycle, which may well mean multiple treatments.
A sure way to eradicate this parasite is to empty the pond and system and leave empty for 28 days, sterilise everything else and discard all plants. You then have the problem of re-hosing the fish, preferably not in a friend's pond, because they may not be your friend afterwards.
Affected fish become very agitated due to the perpetually moving legs of this parasite, fish will constantly flick and even jump out of the water. reddish weal's or inflammation appears at the site of any bite and tumours can form around those areas. Because of the immense irritation caused by this parasite the fish often loose interest in food and will loose weight.
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.
Argulus, commonly known as the Fish Louse is one of the larger crustation parasites, usually 5-6mm or 1/4" in size but can be up to 10mm or 1/2" and is one of the few parasites that can be seen with the naked eye, sometimes resembling black spots. They are oval in shape, greeny brown in colour, semi transparent and have two disc shaped suckers on the underside of the body which are used to attach themselves to the fish. Argulus has four pairs of legs; these are used for swimming, not walking. The parasite clings to the body of the fish with numerous barbs, hooks, spines and suckers attached to its body and legs. You can imagine the damage the various appendages will do, but its most lethal weapon is its mouth.
Their survival depends on being able to feed on a plentiful supply of fish tissue and fluids. To achieve this need they have a very complex mouth arrangement. The mouth cavity contains the mandibles which equate to our jaws, in the centre is the stylet, the sole purpose of this is to inject a type of poison into the fish, this acts as an anti-coagulant to ensure the wound remains open for the next predator. Frequent feeding from the same area by other fish lice and casual agents eventually lead to lesions, ulcerations and is an open invitation to bacteria and fungal spores. If this parasite invades the gill severe damage may be caused resulting in breathing problems and possibly bacterial gill disease.
As Argulus is a free-swimming parasite it can easily transmit diseases from fish to fish within your pond. Frogs and Newts can be culprits for bringing this parasite into the pond; we can unwittingly do it ourselves by not inspecting a newly purchased fish once it has been bagged. Do not let the dealer tell you that your fish is nice and clean, check it yourself, particularly underneath. Adult fish lice are relatively easy to spot, juveniles are more difficult.
Aurgulus is an egg layer, the eggs are laid in thin sticky strips a few centimetres long so they will adhere to the bottom of the pond, or any convenient surface for safety. Fish Lice have a simple lifestyle in comparison with other crustation parasites such as the Anchor Worm, as many of the metamorphic stages take place in the egg. The complete lifecycle is influenced by a number of environmental factors; duration can be up to 100 days, this being largely dependent on temperature. Juveniles must find a host within a few days to survive whereas the adults can survive for as long as 15 days without a host. The female has the potential to lay approximately 1000 eggs so you can appreciate that this parasite is not to be taken lightly.
It is most unlikely that the numbers of Fish Lice will diminish naturally in the pond environment, almost certainly you will have to resort to the use of chemicals to eradicate them. The difficulty being is that you need to catch the full lifecycle, which may well mean multiple treatments.
A sure way to eradicate this parasite is to empty the pond and system and leave empty for 28 days, sterilise everything else and discard all plants. You then have the problem of re-hosing the fish, preferably not in a friend's pond, because they may not be your friend afterwards.
Affected fish become very agitated due to the perpetually moving legs of this parasite, fish will constantly flick and even jump out of the water. reddish weal's or inflammation appears at the site of any bite and tumours can form around those areas. Because of the immense irritation caused by this parasite the fish often loose interest in food and will loose weight.
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.