They look like a higher form parasite to me but never seen before fish appear to be loosing integrity in their scales. Do you have any other symptoms ?
I think I've seen this before. I brought home some sick irridescent cats (with a bad case of ick) and treated them for the ick alone. Over the next week or so one of them developed the same "white line" apprearance as the clown loach in the picture. I was told my the LFS that it could be a secondary infection or it could be a slime coating that the fish is developing to heal (though I personally doubt the second suggestion they gave me ). Till this day I still don't know what might have caused it or what it exactly was for that matter. Scaleless fish are definitely difficult to treat sometimes. Sounds to me that you're going the right route with the treatment you've decided to go on though. I would go with a dose of anti fungal medication (well half dose or less). Hope that things work out for you.
The treatment has gone well and the little clown appears to be recovering.
The lines have all nearly disappeared and he is back out swimming around from time to time now. I'll continue to treat with melafix and pimafix until all signs have cleared up for a week.
Thanks to everyone who responded and helped with ideas.
After what looked like a near recovery, my clown died this morning.
I went out of town for Monday and Tuesday, but on my return Tuesdaynight the clown that had been sick was out playing eating and seemed to be leading the pack of clowns. I was very happy, and most of the lines that had been on his skin were gone!!
This morning he appeared fine too, out leading the pack again, but somewheres between home and my drive to work during an April snowstorm, things changed. My wife phoned to tell that he had started swimming vertically and then sinking back tail first to the bottom, and all the other clowns are staying away from him.
A quick visit home at lunch confirmed that he had died. It is sad, because I could have sworn he was going to pull through after seeing him last night.