A common drawback in dealing with pathogen outbreaks among captive amphibians is the great sensitivity of most species to available medications. Drugs formulated for fish, used as a soak or bath, have great potential. However, amphibians absorb liquids over a much greater surface area than do fishes – in some cases with the entire skin surface – and it is therefore difficult to ascertain proper dosages. Dose reduction is largely a hit-and-miss prospect, as each amphibian differs in absorption ability – medication failure and patient death are all too frequent.
A Malaria Medicine Rescues Stranded Tadpoles
Methylene Blue, a compound that found favor in 1891 as a human anti-malarial agent (and subsequently lost favor due to its propensity to turn the urine green and the whites of the eyes blue!) is one of the safest medications to use with amphibians. It is widely used as a fish medication, but often overlooked by those working with amphibians. I was first impressed by its benign nature when called to rescue several hundred American bullfrog tadpoles from the bottom of a recently drained pond in NYC. The tadpoles had been flopping about for over an hour by the time I arrived, and were all cut up and bleeding.
Without much hope of success, I transferred the tadpoles to several plastic garbage cans and added Methylene Blue at a concentration a bit higher than recommended for fish. Normal procedure would have been to use ½ fish strength and gradually increase the dosage while observing the tadpoles’ reactions, but such takes time and these fellows had little of that. I was surprised to see no signs of stress, and astonished the next morning when most looked quite well. Eventually, a great many recovered.
Use Methylene Blue
I have since used Methylene Blue in private and public collections for a range of amphibians, including Argentine horned frogs, spotted salamanders and Surinam toads. It has been successful against fungus (most likely Saprolegnia) and certain bacteria associated with wounds and “red leg”. I’ve had mixed success in using it to combat fungus on amphibian eggs (smoky jungle frog, bell frogs, poison frogs) – the results likely depend upon the species of fungus involved. I begin with ½ the fish dose and a soak time of approximately 1 hour – gradually increasing both if necessary. For eggs, I dilute the Methylene Blue in water and then use an eye dropper to place it on the eggs (approximately 1 drop per 2 inch square of egg mass).
Treated amphibians will be stained blue for awhile (as will your hands if you do not wear gloves), but results have been very good. Where the compound has not worked, it at least caused no harm, and therefore lent the option of using alternative medications.
Drug resistant strains of malaria have researchers once again investigating the use of Methylene Blue as a treatment option for people. An interesting article regarding this is posted at: