The blue stuff is probably methylene blue, be careful of how much you dose with the eel in there, you should halve the medication with scaleless fish. If your water is clear again you probably have carbon in your filter, make sure you remove this before dosing again.
Exerpt taken from http://freshaquarium.about.com/cs/disease/p/ich.htm
Treatment:
Raise water temperature
Medicate for 12-14 days
Reduce medication when treating scaleless fish
Discontinue carbon filtration during treatment
Perform water changes between treatments
The entire cycle takes about two weeks from start to finish. Higher temps will shorten the cycle, while low temps lengthen it. Therefore, raising the water temp shortens the time it takes for the parasite to reach the stage in which it is susceptible to medication.
Treatments must be given for a long enough period to assure that all parasites are gone. Watch carefully for other infections, as secondary infections often occur where the skin has been damaged by the parasite.
Although nothing kills the parasite once it has checked into it's fish "hotel", several chemicals kill ich once it has left the fish. Malachite green, methylene blue, quinine hydrochloride, and mepracrine hydrochloride are all effective, and are available under several brand names.
Dose based on the package instructions, however cut dosages in half when treating scaleless catfish and tetras. Regardless of the medication used, treatment should be given continuously for 12-14 days to ensure all parasites are killed. Between treatments a partial water change is recommended. Keep water temperatures higher than usual to speed up the life cycle of the parasite. Discontinue carbon filtration during treatment, as it will remove the chemicals.