True Percula Clown w/ Brooklynella
Dear Robert Fenner,
I have recently made the move from a fresh water aquarium to a salt water system, and I love it! By the way, I was sold your book “The Conscientious Marine Aquarist” when I decided to change to a marine system, and I think you did a wonderful job (And I’m not trying to suck up). 
<Thank you. Much good help with this work>
Anyway, I just purchased two true Percula clown fish, a bubble tip anemone, and a carpet anemone. Since introduction, one of my Clowns has acquired this whitish film, almost like his [he’s smaller than the other] skin is shedding. I have read all of the stuff on WetWebMedia that pertains to the clown fish.
I’m thinking that I might need to do a fresh water dip to treat him after reading all of the information. 
<And more... I would resolve/resort to using formalin/formaldehyde in this dip procedure>
I don’t have a quarantine tank to put him in afterwards, but is it ok to put him back in the main tank?
<Mmm, yes, but a likelihood of reinfestation (the system likely harbors/has intermediate forms of this protozoan now.)>
If this is the case what is the best method and additives to use in the dip? 
<Hmm, do seek out a formalin product sold in the trade and follow their instructions (my pick? Kordon's). Barring this, about fifteen drops per gallon of dip of 37% food grade...>
Also, the larger clown doesn’t seem affected, but I received this one with a gold spot on its tail, which has turned into a hole. Is there something wrong with this one, or should I just keep a close eye on it (which I would do anyway)?
<The latter>
I really appreciate your opinion. Thanks - Tim.
<And I the opportunity/challenge of aiding your efforts. Bob Fenner>

Re: True Percula Clown w/ Brooklynella
Robert, thank you for your timely response. I'm out the door to get Kordon's formalin product for my fresh water dip, and I still had a couple questions... 1. What did you mean by "of 37% food grade"?
<Oh, this is a "stock solution" and strength of formalin, formaldehyde in aqueous solution... available in places. Sorry for the confusion>
2. I was planning on using filtered water (the stuff you get outside the grocery store for a quarter/Gallon), is this o.k.? 
<Sure... I use dechlorinated tap... pH adjusted.>
3. Can I use just a gallon of dip, or is better to use 2-5 gallons?
<For one Clown? A gallon should do... and do aerate it during use, and stay there watching the fish...>
4. Should the fish stay in the dip for 5-10 minutes, while watching that it doesn't start thrashing about? And lastly,
<Yes, please read: http://wetwebmedia.com/dips_baths.htm>
5. If the protozoan has infected my tank, is there any way to treat the tank, or is it best to leave it alone? Thanks again. - Tim
<Best to "treat" it by leaving it w/o hosts for a month or more... Detailed on the WWM site... Bob Fenner>

Formalin question
Hello crew,
I recently purchased 2 clownfish and after a week in QT, I believe they might have Brooklynella.  Luckily for me, a friend works in a research lab and got me some formalin.  However, it is a 10% solution.  Since stock solution is normally 37%, would multiplying the dosage by 3 work for formalin dips?
<Mmm, multiplying... as in adding 3.7 times as much as you might will give you about the same concentration as a stock solution...>
I was planning on mixing about 3 (maybe 4?) ml/G saltwater for a 40-60 minute bath, repeating in a few days if things don't improve.  Does this sound like a reasonable plan?
<Yes. Do aerate the water while the clowns are in the bath, and keep checking on them every few minutes>
thanks for the help, as always!
~Jim
<Bob Fenner>

Brooklynella
A few weeks ago I lost three clown fish to what sounded like Brooklynella. All three had been in contact with each other through anemones. The first sign was that they each stopped eating, then they got blotches that looked white and some reddish. I still have a pink skunk which was very close to the maroon that died and yet three weeks later the pink skunk is fine. What causes Brooklynella, why didn't the skunk get it, and is there anything I can do to prevent this again. The other fish in the tank are alright as well, which is a yellow tang and a purple Firefish. I do have a UV sterilizer.
>>
This does sound like Brooklynella (hostilis), a protozoan infestation of mainly Clownfishes. All authors I'm aware of attribute its outbreak and introduction to shipping and stress. Also, it is not susceptible to copper treatment. Formalin baths have proven efficacious, and the friends who I've helped to develop receiving protocols for these animals use a commercial copper-formalin product (Kordon is my fave manufacturer) in a dip/bath to prevent introduction of the ciliate into their systems...
At this point, it may be that due to size, initial health, that your remaining clown is resistant to the present Brooklynella organisms... If they show on this fish, do try a formalin, or formalin plus bath procedure, moving the animal to another tank... and do not place any new clownfish livestock in the tank for a few months. Bob Fenner