For 3% solution epsom salt, add 1 level tablespoon 15 grams epsom salt with 500 milliliters of distilled water. Make sure that the pipette is sanded round so it doesn't damage the fish esophagus. Also when you stick it in the mouth when you feel it stuck give it a little turn and twist the syringe a little then you will feel the small hose coming down a little bit more then inject it.
Imo you should try to treat for an infection. Aquarium salt, raise the temp and maybe some meds. Other more knowledgeable people can recommend some. The whole stress of the syringe process might be too much for a discus to handle. They're really susceptible to stress
Yes you pull him out of the water to do that but you have to try other methods first like Fibblingbear said. If it still not working then you can go ahead and try the syringe method. Here I will give you the video link so you can see. Hes a friend of mine Andrew.
