You are here
Commonly known as "meth blue" or simply "blue," this is a wonderful medication for reversing the toxic effects of ammonia and nitrite poisoning (commonly known as "new tank syndrome"). Since hospital tanks are usually without biological filtration, and ammonia and nitrite can thus build up rapidly (especially if you are not doing water changes during the treatment period), it's a good idea to add methylene blue to your hospital ward when treating sick fish.
Methylene blue also transports oxygen and aids breathing. It facilitates oxygen transport, helping fish breathe more easily by converting methemoglobin to hemoglobin -- the normal oxygen carrying component of fish blood, thus allowing more oxygen to be carried through the bloodstream. This makes it very useful for treating gill infections, low oxygen levels, or anytime your seahorses are breathing rapidly and experiencing respiratory distress. It is the drug of choice for treating hypoxic emergencies of any kind with your fish.
In addition, methylene blue treats fungus and some bacteria and protozoans. Methylene blue is effective in preventing fungal infections, and it has antiprotozoal and antibacterial properties as well, by virtue of its ability to bind with cytoplasmic structures within the cell and interfere with oxidation-reduction processes. A "must" for your fish-room medicine cabinet. However, be aware that it is not safe to combine methylene blue with some antibiotics, so check your medication labels closely for any possible problems before doing so.