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Which dose of methylene blue will be safe for L24? (please give me the final concentration in ppm, mg/l etc.)


*Methylene blue or malachite green - which is safer? If it isn't problem could you tell me the dosage of malachite green (hydrochloride/oxolate) harmless to my L24?

THX for help

What are you medicating for?
-Shane

In NL methylene blue is considered as a source of cancer - and therefore banned. Personally I'm not certain whether malachite green is safe in this aspect. If I remember correctly from books in the period both were used, malachite green is harder to use:

The area where it does have its medical function without being toxic for the fishes is much smaller than for methylene blue

Still, as Shane wrote, firtly what is your problem and than perhaps another medication would be possible

I thought Malachite Green was also carcinogenic.

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Mats

Methylene blue 200 mg/100L only effective to prevent fungus but not really to cure if you not clean the wound and put the Methylene blue directly to the wound with a Topz, kills all bacteria in your filter.

Malachite Green if you make a stock solution, 3 g in 1 L destilled water and from this you use 1 ml/100 L, takes a few protozoa parasites like Ich, keep an eye on the fishes you treat for negative reactions... if so change half of the water, harmless to filter bacteria.

But as the other have written, both is considered cancerogene chemicals andin many countries they are either forbidden or will be forbidden.

And the most important question, why do you want to medicate?

Janne

My problem looks like black spot disease but in freshwater?! I haven't decided yet to start medicating because I don't know what kind of parasite it is... I have raised temperature to 32-33C and I'm waiting for effects.


I asked about doses because I have to prepare stock solutions before i leave my college (where I have analitycal scales) for winter holidays. I want to prepare those solutions just in case

edit:

photo of my oscar with those black spots:

As long as you know the amount of active ingredient in your solution, you should be able to dilute to suitable usage either way - just mix up, say a 10% solution, and then dilute that if you need it weaker.

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Mats

Of course, but I wanted to know approximate value

But if making a correct stock solution directly makes it much easier later, no thinking and it's the correct concentration to be used for all diseases... only the amount that you add can be different.

Anyway, is the Oscar also wild caught? There is a natural worm parasite that use fishes as a middle host and develope to adult in birds. Birds that are infected release their feces into the water where small cristaceans eat of it and they are the first host in this parasite lifecycle, second is fishes that eat these crustaceans and the sign on the fishes is small black spots like your Oscar shows... that seams to have much more than usual, anyway this parasite in small amount is harmless for fishes. If this is what your fish have of course.

Janne

I'm sure this may happen in captive bred fishes if they are kept in outdoor ponds too, right?

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Mats

My oscars aren't wild caught. I also haven't kept them in a pond. This parasite is not harmless, fish show signs of irritation, scratch against objects.

I don't know of anyway to eradicate this parasite and I am sure Methylene Blue wouldn't have any effect.
I think a 10% stock solution is a good one. The exact dose you actually need to use for methylene blue is very approximate. I recommend using enough of the stock solution to tint the treatment tank water dark enough to make a fish difficult to see if it is 6 or more inches from the viewing glass side.
I use about 25% less for incubating fish eggs. Difficult to see anything through 8 inches of water.

Flex wrote:My oscars aren't wild caught. I also haven't kept them in a pond. This parasite is not harmless, fish show signs of irritation, scratch against objects.

However, if they are captive bred in Southeast Asia (as most fish are), they may well be kept in ponds there, and get in contact with parasites.

Sorry, can't help much with the medication.

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Mats

Methylene blue have no effect on parasites even if you add as much that the fishes die, Malachite green has but no effect on capsulated parasites like this worm.

Janne

At the beginning I thought it may be a kind of protozoan infection. I don't want to try any medications until I'll be sure that they will help and be harmless, especially to my plecos.

My oscars are 100% Asian and I have them for 2 years. Is it possible that they have those parasites for 2 years? I have observed that those black spots like to appear more intensive on wounds.

I have seen small black spots among Myleus and Metynnis spp more than any other group of fish. I think they are microscopic, subcutaneous, encysted parasitic worms.
What is infesting your Oscars is not something I have seen before but since they are on an albino Oscars they show up. It may be more common than I know but more difficult to detect among normally pigmented fish. They are probably a stage in a complex life cycle involving several intermediate hosts. They are probably too well excluded from the circulatory system for any drug to reach them in therapeutic serum levels assuming there is even a drug in existence that might work on this organism. There are parasites and microbial diseases for which no cures exist.
I doubt if this parasite is easily transmitted from fish to fish although I can't entirely exclude that possibility. If it is possible I think it would require consumption of the flesh of the infested fish by another. It isn't likely. It is unusual for fish to show any symptoms like those you described for diseases like this. Most of those fish like the Myleus and Metynnis spp showing the encysted parasites as black dots act perfectly healthy but they typically have fewer and larger black spots which are slightly elevated above the epidermis. These are two different diseases.

Compare to the most commercially valuable animal species to man, our knowledge of the diseases of fishes is very sparse. There are viral diseases which have become a problem among Salmonids which are commercially valuable but there are no effective treatments. It could be this is a viral disease. We barely stay ahead of the diseases of man let alone know much about all the diseases of fish.

My oscars aren't albino



In spite of (imo) large number of those parasites fish seem to be quite healthy. Thanks for help, I'll post more photos tommorow.

Flex,
As was pointed out, neither Meth Blue nor Mal Green is going to cure this in any dose. In the case of parasites, the best first step is always a dip in full strength seawater. I would do the seawater dip and then transfer the fishes to a new "sterile" tank. Break down and drain the old tank and let it go dry (filters too) for a couple of weeks. Very few fish parasites can live two weeks outside of water and the key to getting rid of parasites forever is breaking their life cycle. If the salt dip does not work, the next step is a formalyne dip.

Parasites are usually best treated through a short term dip rather than medicating an entire aquarium. This is because the concentration of medicine needed to actually kill the parasites is usually harmful with prolonged exposure. The key will be treating the fishes and moving them to a "clean" environment after each treatment to break the parasite's life cycle.
-Shane