Argulus - Fish Lice


Identification
The fish lice Argulus can be seen with the naked eye and dependant on the species it can grow up to a whopping 1cm, like Lernaea has an exoskeleton made up of Chitin (pronounced "Ki tn"). 

Argulus is a true parasite feeding on nutrients obtained from the tissue of the host by means of a needle like projection called a Stylet. Both male and female are oval in shape, being both broad and flat, the head and thorax are in fact separate although they appear to be as one, (Cephalothorax). Argulus is convex dorsally (top) and concave ventrally (bottom). The underside housing suckers, barbs and mandibles for holding on to the host which causes great damage. Two eyes are located in the head and lying between the eyes and the mandibles is the stylet surrounded by a sheath. (source: http://www.koiquest.co.uk/argulus.htm)

Although it is easy to spot  lice when you know they are there, they are easy to miss in the rush to take skin scrapes. To the naked eye they appear as very small dark spots that are easy to overlook unless they move. They are often found in relatively sheltered areas behind the fins or around the head. They are usually easier to spot on fins rather than the body, as they tend to show up more against a plain transparent background. Lice are oval-shaped and flat and capable of moving very quickly. In an aquarium, they can sometimes be seen swimming as they move from host to host.

Fish with a heavy lice infestation will show a classic irritation response such as rubbing and flashing. At a later stage they will become lethargic. Affected fish may have focal red lesions on their body. (source: http://www.fishdoc.c...ase/argulus.htm)

http://www.bonniespl...us/IMG_2223.jpg http://www.bonniespl...us/IMG_2222.jpg
(pictures by Bill Story)

http://www.koiquest.co.uk/argulus.jpg
(picture by Duncan Griffiths)

Video - http://www.bonniesplants.com/sick_injured_...lus/Argulus.WMV
(video by Bill Story)


Parasite life cycle
As with most fish parasites, they have a high reproductive potential. Mating takes place on the fish, after which the female swims away and lays eggs on plants and other submerged objects. When the eggs hatch the juvenile passes through several metamorphic changes as it develops into an adult. Around 4 days after hatching, the newly-hatched juvenile actively seeks a host and continues its development on the fish. The whole cycle takes between 30 - 100 days depending on temperature. The eggs can over-winter and hatch in spring as water temperatures increase.  Adults can survive without a host for several days. Any treatment plan has to take account of emerging juveniles and therefore prevailing temperatures.  (source: http://www.fishdoc.c...ase/argulus.htm)


M.O.
Argulus will thrust the stylet into the host's flesh to begin feeding. Argulus, when feeding will release a haemorrhaging chemical into the host, which prevents clotting of the blood and keeps the bodily fluids, blood, etc flowing, at the same time Argulus also releases a chemical messenger that attracts other fish lice to feed at the same site and further damage occurs.

Heavy infestations, as opposed to just the odd one or two, of both Argulus and Lernaea are quite common when infection occurs, and is a major cause of secondary bacterial infections leaving serious wounds and the fish very lethargic. The wounds from Argulus heal quite slowly, if at all without outside intervention and will show signs of haemorrhaging. (source: http://www.koiquest.co.uk/argulus.htm)


Transmition
Transmission is by introduction of infected water, fish or amphibians, such as frogs and toads and in rare cases it can be transported on the feet and feathers of birds (a kind of air born transmission).

There are four pairs of swimming legs that make Argulus very adept at swimming and manoeuvring on the host. Argulus must live on the host and almost any region is acceptable, with caudal fins being a particular favourite. (source: http://www.koiquest.co.uk/argulus.htm)


Treatment
Masoten @ 1 gm per 87 gallons over 65deg weekly for four treatments, or below 65 deg, 6/8 gm per 1000 imperial gallons is the treatment that I choose.
Dimilin may be an option for Argulus if Masoten is not available.
Argulus can't stand being dried out so drying the pond and equipment is an option after first removing the fish for treatment to a q-tank.
Salt is not an option as most life stages of Argulus can resist up to 3.5% salinity.
(source: http://www.koiquest.co.uk/argulus.htm)

[From the research, there seems to be two effective treatment techniques - organophosphates and chitin inhibitors.  Organophosphates include Masoten and Trichlorfon.  Chitin inhibitors include Dimilin and Anchors Away.  The tradeoff seem to be that oganophosphates are more effective but also more expensive and potentially more dangerous.  Chitin inhibitors are less effective, but much safer. (source: me)]

thank you so much for posting the actual pictures of lice on a fish.
I have been trying to find a picture and had only been able to find one like the black and white.
This helps alot for identifing a infestation, and now I know what to look for  :yes:
thank you

That's what this exercise is all about!

Thank you for the post!

And thank you Dan!

Karl

Good post and great pics Bill

Bonnie of bonniesplants.com deserves additional credit for the pictures.  I found them on her website.  The pictures are linked directly from her site.  I did not want to copy the pictures or appear to steal them.

Thanks Dan

This was really a good article thanks for sharing so we can all learn! :hello2: :hello2:

great pic.s


I had one of the buggers on a goldfish a month ago and to it off treat the mini pond for them place that bugger in a small cup of water and watch him for a week it live for 7 days with out air or a host in that cup too

I just discovered these buggers on some of my new goldfish a few days ago.  I'm treating with Dimlin.  Looks like Masoten is the treatment of choice.  What's a good source for it?

Follow up to an old post....  most meds are ineffective in a pond with high organic load, so you should clean up the pond up before dosing - and confirm the gallonage of using organophosphates.  Organophosphates are generally less expensive than Dimilin - unless you are buying wettable Dimilin powder in 25 pound bags. 

Both meds are very toxic to invertebrates that form the bottom of the aquatic food chain.  Organophosphates (Masoten/Dylox, etc.) are serious pesticides.  Water changes should be handled with appropriate precautions.  Potassium permanganate will chew up both chems, so treat any waste water before dumping to storm sewers or natural waterways.

Regulatory info:  Pond Care brand Dimilin is approved for use in ornamental fish ponds (no water changes).  The anti-flea pill Program (lufernon) is sometimes recomended to pond owners, but costs more, may not disolve, and is not officially approved.  Purchase of organophosphates may require an applicator's license.  I don't know if they are approved for use in ornamental ponds, but suspect that they are not.  (Regs are stricter for treating food fish - KHA's are officially limited to use of approved meds.) 

FWIW - snails are molluscs and are unaffected by standard dosing protocols of either med. 

Chitin synthesis inhibitors (also called insect growth regulators or IGRs) are VERY effective in clean ponds, and have a very wide margin of safety to fish.  There is no need or reason to do water changes when dosing with Dimilin.  I've always gotten way with single doses, but if the temps are cool, you may need to dose twice.  (Life cycle is temperature dependant; lower temps mean slower development.  The meds kill juvenilles since adults no longer synthesize much chitin, so lower temps require not only multiple treatments, but also that the treatments bespaced further apart.) 

The down side of organophosphates is that you MUST know your water chemistry numbers before deciding to treat.  Organophosphates are popular in areas where the source water is soft and the pH moderate.  However, in hard water or at elevated pH, there is a very narrow safety margin between the dose that is effective at killing parasites and the dose that will cause neurological damage to the koi. Our source water has a GH of 300+ and a pH out of the tap over 9.5.  Dimilin is the only safe option for our local ponds.

Organophosphates are RESTRICTED USE Pesticides , in the US. Restricted means either a Liscense, or a prescription. I f you can find a good Fish Doc, HooAhh!!

But for normal people, get some Dimilin.

And figure on watching for at least 49 days. They are tough bugs.

If you are reading this, you should spend $100 on a quarantine. Sorry.

But to salve you pocketbook, it can take 3-5 weeks for the Argulus to be visible to the naked eye.

BUT..............
Greg
And Please test your Tap water, Please....

Hey Dan,
Favor please...... when time allows can you update the links because I was giving this info to a friend on another forum and see that none of these links are working.

Thanks much,
Bonnie

Thanx for the article. I just found this on a baby's pectoral.


Can these things transfer on snails? I think they are the only thing that has gone in our new pond unquarantined.

Alan

I'm not sure if they come in on snails but they can come in on plants, birds and frogs. Since you don't QT, I would look there first.

If you have one, you have many. Look at all your fish and remove the ones you see. You'll have to treat the entire pond at least twice. The eggs will hatch in about 2 weeks.

Thanx for the reply.

I do normally QT. I put in some trap doors and a spoonflower w/out QT. My bad. Still learning. Now I have to find a source for Dimilin.

Thanks again,
Alan

great pictures Allen!
quick such on line and you should be able to find what you need

You can also use the flea pills Program for dogs. Use 1 large dog (brown) Program pill per 1000 gallons for 2-3 treatments, every 2 weeks. It breaks down the ex-skeleton (cretin?) so they can't survive/reproduce.

Thanks for your kind words re: pics, Meg. http://koishack.com/...fault/smile.gif

Gonna' follow-up w/ Kntry on her suggestion for flea meds.

Alan

Kntry,

Any particular brand of flea med? I REALLY don't want to mess up here.http://koishack.com/forums/public/style_emoticons/default/no.gif

Have not seen any more on other fish so far. Keeping fingers crossed.

Thanx,
Alan

You have to get them from your Vet. They're called Program. You'll need the large dog, brown pill. If you don't have a good relationship with your Vet, he'll probably think you're crazy and not give them to you.

Ok Kntry.. Thanx again, I will talk to her Monday.

Alan

Bonnie, on 14 July 2007 - 12:52 PM, said:

Just saw this and I've fixed the links.

If Dimilin or Anchors Away only affects the juveniles, how do you kill the adults? How long can they live on a fish?

Gloria, it affects the juveniles the quickest because they are molting more often. It makes them not be able to form an exoskeleton. It also affects adults in the same way, just more slowly. I have had to use Dimilin in the past and never had it not work. If the water is cold, you should probably treat twice though, and watch for a reoccurrance in the spring, just in case. The nice thing about Dimilin is the only thing it affects is crustations, so it will not endanger fish at all.

Thanks! I hate pulling out fish in cold weather and my eyes are always saying? shimi or louse?!?!

A long time ago when I had just my watergardens, my fish got lice a couple of times. Each time, the lice showed up on the fins first. And I mean a lot of spots on the fins before any were on the bodies. It is really easy to see them on the fins and there is no mistaking them for shimis there! Maybe that will help a bit. If you see a spot only on one fish and none on the fins, it's probably shimi and not lice.