Like a lot of meds, it will discolor your water, maybe your silicone, and possibly other decor. As to the dosage, I agree those instructions sound unclear. Some meds like malachite green need to be dosed daily to maintain the proper concentrations but it’s possible methylene blue doesn’t “wear off” and need daily dosing. Do yourself a favor and just ask a vet to do a biopsy or at least contact Kordon about proper dosage if your intent on using that stuff. I wouldn’t trust just anyone one a forum if you’re that concerned. But like it was mentioned, it’s best as a bath if you need it. It’ll kill good bacteria as well so you’ll have to keep an eye on your water for a mini cycle.I don't know what happen to the back mybe it tried to jump and hit the glass lid and injured the back. for the methylene blue dosing every day wont the water be blue? I see people just dose once and wait 3 days. that's why im confused on the dosing part