sorry i cant help with the dosing, id go with 1tbsp per 10gal (only replace what you take out with w/c's as it does not evaporate)
callen- sadly everything i have read said that prazi and metro have no effect on camallanus

it would be so much easier if they did!
heres a snippet i took out of my article on it for ya Frances, please note though that this is the dosage i chose to use after many hours reading the various methods, some said to dose for shorter/longer periods of time so i shot for the middle and my fish were fine. sorry it is in litres, its what we use over here.
Levamisole Hydrochloride seems to be the favourite to use but I have seen recommendations of Piperazine and Fenbendazole. The dosage for Levamisole is 1.5ml per 7.5L or water when using a 7.5% solution. I obtained a 24% solution so used 1ml per 22L (not exact but close enough). Levamisole is widely used as a pig and poultry wormer and sometimes a sheep drench. NEVER attempt to pull the worms out the fish- this will rip their intestinal lining as they are securely anchored in there.
METHOD
•Do a 90% water change making sure to vacuum the substrate very well as this is where the nematode young will mainly be. It is reported that the young can be in the water body itself so this is partly why such a large water change is recommended.
•Add Levamisole at the required dose (I mixed it in a litre of water then poured into the aquarium)
•Wait 48 hours (some reports suggested 24 hours, some 72. I decided to go in between). If your fish show signs of not liking the treatment do a water change at 24 hours. My rummies were pale at 48 hours yet the other fish were all fine.
•Do another 90% water change making sure to vacuum the substrate really well.
Repeat in two weeks.
If they are still infested after the second treatment (do note that they will pass the worms so a water change a few days after treatment is suggested as these can contain eggs, I thought this was re-infestment straight after treating when I saw my rummy nose pass an adult worm) you are able to treat again, Levamisole is a very gentle medication and will not harm your bio filters at all. Experiments have showed that over dosing the medication 5 times showed no ill effects but Levamisole does cause intestinal upset at any dose so it is not advised to OD as it can give the fish diarrhoea. Levamisole is totally safe for sensitive fish like plecos, clown loaches, discus etc.
once again this is just my own conclusions from reading many articles on the internet about C. Cotti. hope it help some
