Ich update - day eight

It looks as though the big salty spots have finally leapt from the one zebra danio (we'll call him Fred) that was still covered. Took seven days with temp at 82 and 2tsp/gallon salt and every other day water changes (ammonia & nitrite started sneaking up after I cleaned one of the filters so I've been trying to keep on top of them).

Does ich leave scarring? Because Fred seems to still have faint whitish patches on him - it doesn't look fluffy like fungus, nor is it like the salt granules that were there previously. It almost looks like it's leftover from where the ich was. It looks like one of the other danios has a bit on top of him too even though I never noticed it before (or maybe its just his colouring that I never noticed). Or maybe I'm just seeing things because I've been staring at these fish for a week now non-stop.

Fred also had a long scratch on him that looks like it has healed - just a sliver of a scar but no more bleeding or anything. I bought Melaflix to treat just in case but haven't used it yet.

Lastly, 3 of my remaining 7 danios (one died from major ich) are hanging around the bottom of the tank and not eating. Is this because of the salt? Heat? Slight nitrite rise? (It never got over .3 - haven't tested it yet today) Or is it still ich-related? Any ideas? Should I Melaflix them just to be safe?

If I turn off the light, they venture to the top more often but they still don't hang out there as often as they used to - none of them do.

Humbly requesting advice yet again.

Yep - adding salt to replacement water 2tsp/gallon.

Just tested the water again:

Ammonia - 0
Nitrite - .1
Nitrate - 5

Upon staring at the fish until I was cross-eyed, I noticed that Fred ISN'T completely spot free - still a couple more lingering on his fins. So I'll wait until all signs are gone, then continue with the salt for another week or so. This fish thing is definitely a test in patience, isn't it? And I thought a toddler was!

I also noticed (does it ever end?) that one danio that does hang up at top had a faint white splotch on his upper side. I thought I was imagining it until I looked up from underneath him and saw that it looked like one of his scales was sticking out. Is this something that will heal itself as well?

Update day 9

Update: Things aren't looking good for 3 or 4 of my zebra danios. This morning I noticed that three of them have speckles on top of them (not raised, it looks like discolouration of their scales), one of which used to be covered in ich and STILL has some grains on his side fins (argh - after 8 days???) and one has a large faded patch that takes up nearly its whole side. All the discoloured ones still aren't eating and they're doing a lot of twitching down in the bottom corner (they're hanging out together).

My gouramis and platys? The platys that looked like they weren't going to make it back at the beginning of all this? Completely fine (knock on wood).

HELP!! What do I do??

I've got some Jungle Ick Guard II on standby here (I had a pleco at one point who sadly went belly-up during all of this).

How do I go about diluting the salt? How long does it take?

Here are some photos - maybe they'll enhance my explanations somewhat:

This is the danio with the flake sticking up on top:


This is Fred with his scar and discolouration spots on top of him (spots are kinda hard to see). You can also JUST see a couple granules on his side fins:


Here he was several days ago:


And finally, here's the one with the big faded patch on top:


Any ideas/suggestions? Is this all part of ich or do I have something else in my tank now?