White Spot or Sporozoran?

I need a few opinions and some advice!

I have two loaches (Nimrod who, despite his name, is very loved and probably my favorite, and Priz). I had them for about three weeks in my planted tank when I noticed white spots form on their fins and sides. Originally I thought it was Ich (even as a total newbie I knew about it) and set to start treating it right away. However, about several days later, I noticed that literally none of the other fish had contracted the ich at all. Not a single spot on them-- just these two. Of four Gourami and a zebra loach (whose two buddies did not make it) only the Gold Zebras had the white spots, and the spots have not gone away at all from the time they've had them. They do the typical skirting/rubbing behavior characteristic of fish with ich, but I can't help but wonder if it really IS ich as I recently read a few articles about white spots on fish that aren't ich. I'll attach a photo or two of Nimrod and Priz as they are now. Please tell me what you think! (Photos taken 5 or so days into medication process as the heat method did not work)

[waters are tested and perfectly fine except for the nitrite level being slightly high but I've just done a 26% & 1 50% water change three times over the course of a week to help get rid of any potential ich floating around so the levels are good now.{

 

I'm treating them with a medication called Ich-X.i can post a picture of the listed ingredients if it'll help.

The one that's really skinny is Nimrod; he's been refusing the wafers so I've been giving him diced cucumber, but he only nibbles it occasionally and only seems to want the Gouramis' food that only floats downwards occasionally.

I meant to post 25%, sorry. I did 25% changes on Thursday, Friday, Saturday and today, and then the 150% was actually 1-50% meaning one 50% water change on Wednesday. Sorry, I made that pretty confusing to read.

 

Alright. Thank you very much! Was this probably the result of a deficiency of nutrients provided by the frozen food? I'd like to know for future reference if it isn't too much trouble.

 

Update:

The loaches are now clear of white spot and excess mucus!! Nimrod (Loach in the wisteria) has also gained back his weight and is parasite free!

[ps, super excited!! They'll be getting some real cool friends I've had planned to arrive for a while, and a LOT of plants to provide more hiding places. Keep an eye out for when I post their arrival ]

 

Yep! They've all already been quarantined for a few days, but I'm gonna give them an extra two days with the recent scares I've had with the tank just to make sure

 

I know

Their 2-week quarantine is almost finished, and I've had the plants in quarantine for longer than the stock so I added them in tonight to let them sit and adjust a day or two before the fish join.