White Spot Debate

[Powder Blue]

Dear Members,

Please may I have some input on this horrible parasite that seems to hound us all. These are my experiences in this newish hobby of mine and some questions.

I live by the East coast of Africa in Durban South Africa and have tons of good clean sea water avaliable for changes on the low tide. I have read that white spot is a parasite that needs a host to survive and if it cannot find one within 3 days it dies off. Sooner if I bump the temp up to 33c.

What I do with new arrivals is they stay in my hospital tank for 3 days at 30c with a solution of copper in the tank to rid of any potential White Spot if any. Then I add the fish into my main. With water changes I collect 200l of water of the ocean and let it stand for a week before filtering futher and adding to the main. This process, even though a bit of work, has removed all the parasites from my tank I assume as I have never had an outbreak or ever seen even one spot on any of my fish for 6 months now. It is cheaper than using salt and RO water.

Does this make sense???

A petshop manager once said to me that O.Odinium and White Spot is always in the tank and I don't agree. How do fish sudenly aquire White Spot? I know our local suppliers pump the fish in and out there tanks before they are checked properly or treated.Business as usual.

Would you say that even Itch prone fish have a better chance of survival this way? An example is my new Regal Tang and past Powder Blue Tang never had a single spot when first introduced and while settling in. Both fish are apparantly very sensitive to the parasite.

[Ninong]

I have read that white spot is a parasite that needs a host to survive and if it cannot find one within 3 days it dies off. Sooner if I bump the temp up to 33c.

Both Cryptocaryon irritans (white spot) and Amyloodinium ocellatum (marine velvet) are protozoans that require fish hosts to complete their life cycle. The maximum length of time that the theront stage of C. irritans can survive while swimming around looking for a fish host is 18 hours, even less if the water temperature is raised. The higher the water temperature, the faster the life cycle and the shorter the time in each stage. See my replies in this thread for complete life cycle: White spots.

With water changes I collect 200l of water of the ocean and let it stand for a week before filtering futher and adding to the main.

Even 24 hours would be sufficient to guarantee that there are no free-swimming theronts in the water. However, allowing natural seawater to stand for a week so that all of the plankton dies off is the safest way to go.

A petshop manager once said to me that O.Odinium and White Spot is always in the tank and I don't agree.

This is a common belief that is especially strong among people who have experienced repeated outbreaks. Common sense tells us that it does not have to be true and shouldn't be true if proper steps are followed to make sure the parasites are completely eliminated. This would require allowing the tank to remain fishless for a period of at least one month, two months if you want to be super cautious. The life cycle is broken if there are no hosts (fish) in the tank.

How do fish sudenly aquire White Spot?

Maybe they had a very low level infestation that wasn't noticed. Maybe there were viable tomonts in the tank attached to the substrate, tank walls, equipment, rock, etc., that had not yet hatched into tomites. Maybe water containing live tomites was added to the system. They can't get it simply because they are stressed out but they are certainly much more susceptible to getting it if they are stressed. You still have to have some available theronts swimming around in the water column looking for a fish to attach to. Either that or your incoming fish already had a few trophonts hidden in its gills and the new stress caused it to be more vulnerable. The trophont stage lasts about a week attached to the fish.