I picked up a bottle of Kordon Methylene Blue(2.303% solution) after reading one of your replys about using it as a preventative on new fish.Do you recommend its use in saltwater or freshwater(reef fish) when used as a dip?Is it just for a preventative dip before going into quarantine,or do you treat the QT tank?Can you give me a recommendation on how much per gallon.The instructions on the bottole are pretty vague.

Thanks,

Sue

I seldom if ever dose a QT with anything medications - only exception would be copper.  I always prefer to do baths.  Most medications do lose their potency when exposed to light and saltwater.  Most will affect or totally wipe out the biological filtration - methylene blue being one that will wipe out the biological filtration.

I use the methylene blue in a freshwater dip before the fish is placed into a QT.  The methylene blue does help eliminate some of the external parasites and does help with nitrite toxicity and oxygenation.  I perform these baths for a minimum of 15 minutes but aim for 30 minutes.

I have not used the specific brand of methylene blue that you mentioned but the 2.3% strength is pretty "standard".

The recommended dose is 3.7 mg - 11.1 mg per gallon.....okay here is the math conversion (math geek coming out in me )

2% = 2 gm/100 ml

so that = 2000 mg/100 ml

so 1 ml = 20 mg ......   and 1/2 ml (0.5 ml) = 10 mg

So with your standard solution (~ 2% ) you would add roughly 0.19 ml to 0.55 ml per gallon of water.

Hope this helps.

The dose of oral praziquantel is 23 mg per pound of fish weight so:

1 pound = 0.45 kg = 454 gm

so the dose is 23 mg per 454 gm.

so a 19 gm fish would require 0.96 mg of praziquantel.

Shake vigorously before use.
Measure at the rate of 1 tsp per 20 gallons. One ounce per 120 gallons. This produces a concentration of 2.5 mg/L.
Distribute the proper amount around the edge of the aquarium or directly into the filter box to achieve the best overall distribution.
A single treatment lasting 5-7 days is normally sufficient. Repeat as necessary, but no more than once every 3-5 days.
May be used as a preventative at the standard dosage, when disease is likely.
Do not use any other drugs or disease treatment.
May cause noticable temporary foaming.

Specifications:
This is a ready-to-use, liquid concentrate that was developed as an effective way to deal with unwanted parasites in ponds, freshwater or saltwater aquariums. It is extremely safe and super effective giving you rapid control yet will not negatively impact your biological filtration.
Key benefits: treats flukes, tapeworms, flatworms, turbellarians; can be used as a preventive; non-toxic to commonly kept aquarium animals or plants.
Treats up to 120 gallons.

Ingredients:
Oxybispropanol (as an inert solubilizing agent) and <5% praziquantel by weight.

Hikari Prazi-pro comes in < 5% so < 5 gm per 100ml which :

< 1000 mg per 20 ml = <50 mg per 1 ml

1 gallon = 3.7854 liters

SO:  if one does not dilute per above instructions ~ 0.019 ml would = 0.96 mg

IF one dilutes according to directions (2.5 mg per liter):

 a 19 gm fish would need 0.384 liters = 384 ml of the diluted Prazi -pro (1 teaspoon per 20gallons).

Hope you can follow

Best of luck

I have a food scale that measures in grams as well as ounces.   What type & size fish are you wondering about the weight?  If you buy praziquantel from the vet - it comes in tablets (smallest - 23 mg I believe).  In case you haven't heard, praziquantel is not inexpensive either.  As far as how much to add - weight of fish multiplied by 23 mg divided by 16 (16 ounces in a pound)....this will give you the mg dose you need to add/administer to food.  See above post.  If one is having difficulty figuring out dosages, please post & I will be happy to figure out for you.

If your fish has spent a long period of time in the bag (i.e shipping), I would recommend acclimating the fish to a "normal" pH water with the same salinity.    After the fish has been acclimated to water with a normal pH - then I would proceed with the freshwater dip. 

I use freshwater dips with methylene blue on all new specimens before they are placed in QT.  I believe that this helps remove some of the external parasite load if there is any.  I only treat prophylactically with hyposalinity those fishes that are "ich magnets" - puffers, tangs.  After the freshwater dip, they are placed in the QT that has a salinity slightly lower than the salinity in the transport bag.  If I am treating with hyposalinity,  the salinity is lowered slowly over 8 - 10 hours.  I think this causes less stress than freshwater dip to hyposalinity especially in a fish that has been shipped.

Hope this clarifies..............