Some of the negatives regarding use of the drug includes the general condition of the fishes living quarters. Crowding and over feeding generally gives rise to the greater population of the intermediate host. This is generally the Cyclops. They are often too small and fast for the guppy to clean up and many remain to reinfect the untreated tanks and fishes. My general regiment of treatment includes water changes both before and after treatment. This has caused much distress in many of the affected fishes since many of them have never seen fresh water and pH shock and drop in dissolved solids takes out the diseased fish before the treatment can be made.

This points to one of the greatest concerns of mine with regard to the general tropical fish keeping hobby, that of simple Husbandry. Flushing the toilet once in a while is enormously important. A highly infected tank can get make quite a load of dead things to deal with and the water must be changed to get the bacterial food eliminated. If the fish have never seen fresh water that by itself could kill them.

And then there is the Chlorine issue. It appears that many fish keepers have a notion that the present Chloroamine can be removed by overnight aeration. Nothing could be farther from the truth. As a matter of experience, tap water here in St Louis remains lethal for 3 to 4 weeks when done that way. I don't wish to get into the Ammonia battle here, but activated charcoal or chemical treatment is necessary to remove present day Chloroamine, and checking for Chlorine in the treated water is advised. Better safe than sorry. But the water still needs to be changed.

How effective is internally treating fry with an external application of an anthelmintic?

That depends on the expected results and the drug used. The water contains the drug and small amounts of that water are consumed when eating. If this is not enough to kill the parasite then there must be some adsorbed by the gills, etc. since the dose of Levamisole does the job. In some contrast, the drug Flubendazole is effective when adsorbed by the fish. This drug effective removes the intestinal parasite, Hexamita, even though the afflicted fish can't swallow due to irritation of the gut. My research has not shown the drug Flubendazole is or is not as effective as Levamisole in treating Camallanus. More case histories need to be studied.

Removing the "Dead" worm physically from the fish is NOT advised. The worm needs to decay or at least turn loose of the intestinal tract. Otherwise the hooks of the head of the adult Nematode may rip open the intestinal wall and kill the patient.

Prophylactic treatment of central filtration systems at wholesaler places and shops has two faces. One, the treatment may be extremely helpful to eliminate the majority of the potential parasites and on the other hand, the resident time the parasites spend in the medicated environment and the concentration may not be sufficient to kill 100% of the bugs and the survivors could show significant resistance to the drug in the next treatment. This could be VERY dangerous.

Given adequate concentration of either of these anthelmintics AND resident time, the drugs will eliminate the parasites from the corners of the tanks etc. The solution must flow through the corners of course. But, the Camallanus parasite is a Nematode. This requires a secondary host. Often these secondary host are very small and miss detection. There is also the free swimming infectious stage of this Nematode. They are certainly not to be seen. Full treatment can be effective to eliminate the Nematode, but both concentration and resident time are required.

More information and previously published papers are available on the website   http://www.inkmkr.com/Fish

I hope this answers most questions and helps to eliminate the pests.

Regards,
Charles H Harrison, Ph D

C. H. Harrison, Ph. D.
319 Martigney Dr.
Mehlville, MO  6319