The Puffer Forum

If the fish is still eating, treating the food is a lot more effective than treating the water.

However, if the fish is no longer eating, treating the water or force feeding are the only remaining options and treating the water can work, I've done it, I've had friends who have done it. It just takes longer and isn't as effective, but it can get the fish healthy enough to start accepting food again, at which point you can go the more effective route of feeding the treated food. Hopefully most people realize what their problem is and start adding dewormer to the food before it comes to the point that the fish no longer eats.

What does it mean when the puffer's lips turn dark?

Not sure what you are referring to. Is the area around the DP's mouth dark? Or is the belly dark as well?

It's just the lips, kind of as if he has a bruise... Perhaps it's food in his mouth? but it doesn't look like it.