I've now put my guppy in a bag inn the tank so I can medicate him (bag is around the hatchery box) and not the others. The medication is interpet swim bladder treatment, and says it's a 4 dose treatment to repeat on days 4,8&12. After the full course do a 30% water change! My question is, if he is in his own water, does that mean I leave him in that water 19 days before changing it?