[jbicb3]

Has anyone used this on Tangs? And what is the process?

What is a fresh water bath? How long do the fish stay in it?

[Ninong]

Originally Posted by jbicb3

Has anyone used this on Tangs? And what is the process?

What is a fresh water bath? How long do the fish stay in it?

I have no experience with methylene blue but I understand that a few hobbyists have used it in freshwater baths. It is a blue dye that oxygenates the water and makes it so dark that the fish are calmed down during the freshwater bath process because they can't see a thing.

Obviously it should never be used in the main display tank because it is reportedly toxic to nitrifying bacteria.

I don't believe I would ever use it myself but that's just a personal observation.

A freshwater bath means that the fish is removed from the main display tank and placed into a much smaller container of pure freshwater that has the same temperature and pH as the main display tank, except that it's freshwater instead of saltwater.

A freshwater dip (as opposed to a freshwater bath) means that the fish is simply dipped into the freshwater for a brief period of time. A freshwater dip may last 10 or 15 seconds, a freshwater bath may last 10 or 15 minutes. How long the freshwater bath lasts depends on two main factors: (1) What you are trying to accomplish, and (2) The ability of the fish in question to tolerate the procedure.

Freshwater dips and/or baths are often used to remove ectoparasites from fish. Some people use them in a prophylactic manner on incoming fish before placing them into the display tank -- especially if they do not have a quarantine tank. I have never used freshwater dips or baths myself because they have never been necessary and I don't believe in dipping fish unless there is a specific reason to do so.

Before you do any of these things, you need to know exactly what you are trying to "fix" and whether a freshwater bath would have any benefit or not. I am not sure what your problem is based on your description of brown splotches in your other thread. Most ectoparasites are white. Marine ich would appear as small (approx. 1/16" diameter) white dots on the fish. Marine velvet would appear as white patches on the fish. Tubellarian worms (sometimes called black ich) would appear as small black dots. Endoparasites are unseen, so it's not necessary to describe them.

I will take a wild guess and suggest that what you have, based on your description, is something brought on by poor water conditions. It may be bacterial in nature. It may require treatment with one of the antibiotics in a separate tank or it may go away simply by doing a few water changes over the course of the next week or two and trying to maintain good water parameters.

I noticed from your other threads that you recently purchased this 75-gal tank (9/29/04) and that you lost a damsel during the set up process. I believe this was a tank someone else had for about a year or so and they wanted out of the hobby. You posted pictures of a diatom bloom, which is a perfectly normal thing that happens during the cycling process. It takes time for a tank to complete the initial cycle. It is best to hold off on adding any new fish until the tank has been set up a minimum of five weeks. It appears that you added these two tangs to your newly set up 75-gallon tank less than three weeks after starting it up. That could explain the problems you are now experiencing. Tangs are noted for being susceptible to various parasitic and bacterial infections caused by the stress of handling and immature tank conditions.

At this point, my suggestion would be to forget the freshwater bath unless you know why you are doing it. I'm not sure it is indicated here. My suggestion would be to feed your tangs lots of greens soaked in vitamins. By "greens" I mean any fish food that contains spirulina, fresh broccoli (blanched for 20 seconds in boiling water first or frozen first to soften it up), nori (seaweed used in Japenese cuisine -- unseasoned), etc., and do a 20% water change with saltwater that has been aerated for at least 24 hours first. You might want to do a series of 20% water changes, perhaps three or four of them spaced five days apart.

It is important that you know what your water parameters are. This requires good quality test kits. The LFS probably has a pH probe and they could give you an instant reading on that but they may not offer any other testing. You need to know what your nitrates are and it would help to know exactly what your calcium and alkalinity levels are just in case one of those is way out of whack. The calcium and alkalinity are probably not causing your problems unless your alkalinity is extremely high or something like that. Your nitrates should be maintained below 50 ppm for a fish-only tank. Lower than that would be better. And you need to know exactly what your salinity is. If you are measuring specific gravity, you should keep it between 1.023 and 1.025 for a fish-only aquarium.

That's about it. It's hard to say exactly what your problem is but my guess is that it is related to the fact that your tank is not even a month old yet. And let me be the first to suggest that two tangs is a 75-gal tank is not a good idea. It would have been better to stick with just one yellow tang instead of a yellow and a sailfin.

Good luck,

[ClintoninCali]

Methylene blue has been known to dye live rock and corals. I had a friend that used it in his semi-reef tank and it cyed his atlintic anemone an awesome shade of bright blue. It only lasted for about a month but it looked kind of cool.