Medication for internal parasites without treating food?

[foshizzle]

I have a mandarin getting skinnier even though he eats pods constantly. For 4 months, he's been active and appears normal except for the weight loss so I'm guessing it must an internal parasite of some sort.

He's not interested in outside food. Is there an effective water treatment?

 

[ThRoewer]

All saltwater fish have to drink from their surrounding water.
So all you need to do is dose the water and he will ultimately ingest it.

 

[Dmorty217]

Prazipro

 

[Deinonych]

Prazipro

+1

Metronidazole has also been used with success by a number of users here.