Been posting a lot on this section for help, so sorry in advance lol. Tank parameters off the bat: Ammonia 0, Nitrite 0, Nitrate 10-20PPM, PH 6.8-7.0 I recently finished cycling my tank, and added 4 danios last Thursday. Drip acclimated for roughly an hour before adding them to my tank. One of the four was acting strange off the bat, sitting alone, not really swimming around. I had a bad feeling about him and it came true, that Friday morning he was dead (stuck to the filter). The other three were fine, eating, swimming around, chasing each other being typical danios. One of those three has had a weird mark on his dorsal fin, I've noticed it ever since I brought him back from the store. He's been doing fine, however today since I've gotten home from work he's just been sitting there, chilling next to the filter current, doesn't seem to be gasping for air or anything, just sitting near the top, swims a few circles every once in a while and goes back. I'm not particularly experienced, so I have no idea what this mark on his dorsal is, doesn't look like Ich, its brown and not exactly salt grain sized. He's also got what looks like a little bump, right in front of his dorsal could it be fin rot?: Click for full size And then, I noticed a whiteish spot on one of my other very active danios along one of his silver stripes. I actually noticed this spot on saturday, and it hasn't seemed to have spread. Not sure if this is Ich or not.., its definitely white though: Click for full size I don't want to start treating for ich or whatever they might have until I have an opinion from you guys, could be a scrape or something, but I have no idea. Thanks for all the help.