Dont want to loose it

Oh and tetragrammoton is only half correct, you can germinate things fine in the same pot, but you have to transplant fairly quickly otherwise roots get entangled and THEN they compete for the same space/nutrients/water/soil. And they have no issue being transplanted at that stage. I recently transplanted 18 seedlings that germinated in a 30cm radius pot wit heavy clay, outdoors, when they recently had rain and it's cold (like 5c minimums). Here's an image https://media.growdiaries.com/static/post/photo/87897/4130744_grow-journal-by-sir-isocustomcustom.jpg , it's in my "some randoms I cooked" diary, and I'm doing crazy shit to them. So, personally, I would recommend you transplant that to different "clean" soil ASAP and reassess method (watering, lighting, nutrients, if applicable) if that is recent damage and/or worsening, coz those "yellow tips" aren't really yellow, those parts are outright dead. If I had to guess though, it mostly looks like watering, heat, light related...but since there's no info, I can't say. Which is a bit sarcastic, btw. Coz there are other seedlings in the same pot, doing fine. So it might be a little pocket of excessive nutrients, maybe even root damage.. Impossible to know from the info, but "coco mix" is like saying "they're growing in stuff".