Originally posted by TerryB
Terry,
TB: Gheez,
I didnââ"šÂ¬Ã¢"žÂ¢t want to come across as being too critical because I felt that the article was better than most that have appeared in the hobbyists magazines. I encouraged Steve in another post here. However, since the subject has been breached I will join in the conversation.
I am only raising these issues in an attempt to make the article even better than it already is.
TB: I only use the 28 or 30 day period as a time frame in which to keep the display tank without fish in order to starve the parasite out for lack of a host. I can understand why you would feel it is necessary to treat fish for 6 weeks by your thinking. However, when the aquarium is kept at 14ppt the tomonts will be destroyed (literally) so a longer time frame should not be necessary.
My comments and scenario directly relate to the section in the article on quarantining at normal salinity. Certainly, if you lower the salinity you have the potential to shorten the quarantine period, but if you don't, 28 days is potentially too short. If you go to the trouble of having a quarantine tank AND you have already kept new fish there for 4 weeks, what's an extra 2 weeks? What's an extra 4 weeks? It all becomes relative and it is a matter of weighing up the risks - probability of occurrence versus impact of occurrence - standard risk management.
Maybe you can enlighten me as to how a salinity of 14-16ppt could cause kidney failure to bony reef fish? A lower salinity in the surrounding ambient water that is closer (still somewhat higher) to that found in the internal fluids of the fish should actually require less effort by the kidneys while still allowing them to function in a normal manner.
I think you need to reread what I wrote. Here is is again:
"I agree in the kidney failure
potential for
stenohaline fish."
(I added the bolding.) I am not saying that kidney failure will occur for bony reef fish. I am saying that it could be a possibility for stenohaline fish.
I am not a fish physiologist - although I did study some marine physiology as part of my degree. I can't comment either way on whether kidney failure can occur in marine teleosts.
By definition, stenohaline organisms can only tolerate a very narrow range of salinity. Whether this limitation manifests itself in kidney failure, loss of salts, bloating or whatever when a marine stenohaline is moved to lower salinity (outside its range) I can't comment, but something will fail. Euryhaline organisms on the other hand (and again by definition) can tolerate a much wider range of salinity and so should have no problems adjusting and even surviving in hyposalinity.
My point to Steve was not whether kidney failure was or wasn't a potential problem, but that if it was, it should only be a problem for stenohaline fish. It has always been assumed that reef fish are stenohaline, but the research by Woo and Chung (1995) demonstrated that for at least one common aquarium species of reef fish, the assumption is incorrect.
It should be noted that the kidneys of marine teleosts are not responsible for the removal of sodium and chloride from the blood. These salts are actually removed by the gills - or at least special cells in the gills. The marine teleost kidney removes magnesium and sulphate. I don't know if this causes a potential for kidney failure or not.
Also note that the sodium concentration in the blood of elasmobranchs is also significantly lower than that of seawater and almost all elasmobranchs are stenohaline. They load up their blood with urea and TMAO to make it isosmotic with seawater. Despite this, there are a number of species of euryhaline elasmobranchs. So ionic concentrations of the blood shouldn't be used to determine if an organism is euryhaline or stenohaline.
I am also a bit concerned about the idea of there being more than one species of Cryptocaryon irritans, this has not been established. It is pretty well agreed upon that there is more than one strain of the parasite, but not enough differences between them to call them distinct species from one another.
I don't believe enough research has been done to make a comment either way. It has only just been determined that
C. irritans does not belong in the same family as
Ichthyophthirius multifiliis (Wright and Colorni, 2002), so there is still plenty of room for further research.
You know, all this discussion between three "ich aficionadosââ"šÂ¬Ã‚ such as ourselves could be dangerous. The next thing you know, we will be critiquing all of each others articles. Then we wonââ"šÂ¬Ã¢"žÂ¢t be able to write anything without consulting one another.
I only see this as a good thing, especially since the research is not our main occupations. (Professional scientists can get quite competitive when there is money or patents involved and a number I know who used to be close colleagues of each other are now sworn enemies.) Having a number of people with a deep interest in a certain subject will ensure we keep each other honest and will also help us have common knowledge and understanding on the subject. I know I picked up a couple of extra references from Steve's article.
) and won't make much difference to the average aquarist's use of the information.
