The Effect of Temperature, Salinity on the cryptocaryon irritans

[snorvich]

I was intrigued with the question of using temperature as a life cycle accelerator of cryptocaryon irritans or inducing mortality on cryptocaryon irritans. Well having spent the last hour and a half on Google Scholar, I have looked at various peer reviewed studies of the effect of temperature on the development of the various strains of Cryptocaryon irritans. The simplest was published in the Journal of Fish Diseases volume 2 issue 2 on pages 93-97 of March of 1979. A simplified and shortened abstract follows.

Trophonts of one of the variations of Cryptocaryon irritans (Brown) from infected three-spot damselfish, Dascyllus trimaculatus Ruppell, were kept at temperatures ranging from 45° F to 98.6° F to observe encystment and development of the tomites. At 86° F, 77° F and 68° F, the percentage of trophonts that had encysted in 16 hours were 70, 77 and 64% respectively; at 98.6° F, 44% encysted and at 44°F only 10% had encysted.

The optimum temperature for excystment was 86° F; 50% excysted in 5 days and 100% in 7 days. At 77° F, 60% of the tomites started to excyst on the eighth day, and 70% on the ninth day. At 68° F, 10% started to excyst on the ninth day, reaching 40% on the tenth day. No excystment occurred at 98.6° F and 44°F.

Newly encysted tomonts were placed in various dilutions of sea water (31 %0) and kept at temperatures ranging from 44°F to 98.6° F. Low salinities, i.e. 16%0 and lower caused tomonts to rupture. At 98.6° F, 68° F and 44°F, 35% of the tomonts started to rupture immediately in 50% sea water, while at 86° F and 77° F, 30% of the tomonts ruptured in 25% seawater. However, none of the cysts developed normally at these dilutions. The percentage rupturing increased with decreasing salinity.

[snorvich]

And the literature also pointed out an interesting fact with regards to the different strains of the parasite. It seems that strains were geographically situated which explains why mixing fish endemic to geographic locations can occasionally introduce more than one strain of cryptocaryon irritans and why they may react differentially to salinity differences.

[Oscar85]

Thank you for all you post about fish disease. I have been reading for hours.

I'm now feeling confident regarding fish quarantine techniques however what about adding coral frags or sps with potential torments attached?

Above you have mentioned low salinity ruptures these but over what period of time? a dip?

What advice can you recommend to treat these regular additions into the display tank?

Thanks again

[ThRoewer]

I'm afraid Steve is no longer with us.

To answer your question about corals:

Option A: quarantine them for at least 3 months in a tank without fish. Good thing is that you don't have to restart the period when adding a new coral to the QT.

Option B: have the store either cut you a fresh frag or have them cut off the frag plugs/base rock. Fish parasites can't encyst on living coral tissue (they would likely become coral food) but only on dead/exposed parts of the coral skeleton or the uncovered base rock or frag plug.

With most SPS and LPS like Fungia I would try to go with option B while most LPS with exposed skeleton likely require option A.

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