First time grower and confused

These are 12 days old im using coco they got their first feed on day 8 i done a quarter does, does anyone have any ideas what the issue is don't want my first crop to die. I do have a leaf mutation but I think its just how it grew. My big healthy one is showing early signs of it and my little one just ain't growing.

It's actually really easy to overwater with coco, that's the main cause of any issues at this point in a grow. I would have started by adding some perlite to that coco, but that won't help you now...just think about adding perlite to the mix when you transplant. Few questions: what is the PH and PPM of your water? Are you testing it each time you water, and have you added any nutrients yet?

Thanks for the reply. I bought all the things I needed in one order and forgot solo cups and perlite was gutted I've got it for transplant. I ph every time and keep that between 5.5 - 5.8 I used my tap water for a first watering and that was hard about 700ppm then used spring water with canna coco a&b and rhizotonic quarter of recommended dose then some ph down the ppm was about 850 didn't add calmag because of how hard my water was and because of the ppm, I definitely watered early the second time because they were over a week and needed nutes. I must say I have budget testers i dont trust them much the ph pen seems spot on the ph of the water is 7.8 and it reads that but not sure about the ppm meter

That's a high ppm for those little seedlings, is your base water ppm 700? If so, that's the problem, if not, then you need to reduce your next feed ppm down to like 300 or so. Also, until the roots fill out it's easy to overwater in coco, esp without perlite, so go by weight rather than if the surface is dry.

Yeh 700 out the tap so I bought bottles of spring but they come out at 300 I might need a more expensive ppm meter I've calibrated it with the liquid and it showed 1413 so seems ok. I'll just use coco a&b no rhizotonic keep the ppm down when they feel light

What size containers are the plants in now?
If you want to know the correct way to grow in coco, this is the best place I know.........www.cocoforcannabis.com.

2gl - 7.5L they are a bit big I forgot the solo cups some people grow photos in final container and they do alright so I thought my mid size ones would be alright. Thanks I'll check it out