[dougc]

Having never seen this particular problem until recently, I am wondering how common it is. Last winter, I brought home an Atlantic blue tang and put it in quarantine. After about a week, I noticed that the fish had some discoloration on it's sides. It did not look like a bacterial infection and, after some research, I took a guess that it might be flatworms. Don't ask me what led me to this conclusion, since I don't remember any more. I did a freshwater dip, to which the fish did not react well, but off came clear flatworms by the dozens. I repeated the dip a second time a few days later, but did not see any more flatworms.

Fast forward to about 3 weeks ago. The Atlantic tang, due to its belligerent behavior (the most persistent bully I have ever seen), earned a free, one-way trip back to the LFS (the same one where the fish was purchased). With the help of the credit from the returned (and grown out) fish, I came home with a mimic tang (Acanthurus pyroferus). After a few days in QT, this tang started exhibiting similar symptoms. A freshwater dip confirmed my suspicions as, once again, the flatworms fell like rain.

Given that the two tangs are from different oceans, I would assume that the LFS has an endemic population of these nasties. If that is so, why did my Atlantic tang not get reinfected after the first dip, since it went right back into the QT tank. The store in question also broke down their entire fish system last summer, which I would expect to eradicate any pests like this.

Having kept quite a few tangs over the years and never having run across these flatworms before, I am wondering whether I am just unlucky now or was just lucky in the past.

[leebca]

Originally Posted by dougc

I am wondering whether I am just unlucky now or was just lucky in the past.

Sort of neither one, actually.

I began my saltwater experience in 1968 (if interested, see: Bio - Lee (a.k.a. leebca)). Imported fishes were better cared for in the handling process even though many were caught using cyanide. This has evolved into fewer caught by cyanide and more of them less cared for in the handling. The fish have become more of a commodity. They are caught, brought into much closer contact with other fishes, weakened stored or shipped together, unlike 'the old days.' Add to this the fact that old means of 'keeping fishes in the system healthy' are becoming less effective (e.g., the cavalier use of antibiotics have bred antibiotic-resistant strains of microbes). The net result is that fishes are coming through the system more often diseased than not diseased.

The LFS is left to struggle with this. But the fish is a commodity and the LFS only needs it to live long enough to sell. So the LFS may resort to using copper routinely in their system just to handle the 'fast killing pair of parasites' (Marine Ich and Marine Velvet). Flatworms will take their toll on a captive fish, but it usually takes weeks or months. So, the LFS doesn't really have to deal with such parasites, especially when the public is so unknowing and most don't still use a quarantine process. The LFS simply claims the problem didn't come from the sold fish, but the fish already there.

This is why I've turned to the acclimation procedure I've posted which includes a FW dip for all new fishes. All too often I see those worms in the FW dip water from fishes I would not have suspected to have them. None of these parasites are in my display tanks. After the FW treatment, in quarantine all are de-wormed. For Tangs, all then are automatically copper treated.

I can't being to speak about the hundreds of fish I'm sure I 'saved' by this process. The experienced aquarist knows what the novice ones are learning -- the LFS is just a shop selling a product that in this case, happens to be alive. The life is expendable in the eyes of those who handle the fish. Only the minimum will be done to maintain the product quality.

If the LFS pays $5. for a fish it sells for $40+ how many can they afford to 'throw away?' The collector in some countries gets pennies; the exporter gets $1.50, the wholesaler sells it for $5. and the LFS hopes to sell it before it dies. The wholesaler can also strike another deal with the exporter -- getting up to 15% of the order replaced for free or credited for dead-on-arrivals.

Back to the subject. . . There are dozens of different kinds of these worms. Some reproduce on the fish, others go through a free swimming stage. If the type on the fish being treated is truly one of the 'on-the-fish' types, the FW dip of the fish removes the parasite from the tank more than about 95% of the time.