Yellow cotyledons????

So I just germinated some new seeds on Sat. and yesterday a couple seeds had cracked and were showing taproot so i placed them in rockwool...
today, one of the trainwreck seeds broke through the top of the rockwool cube and the entire seedling is yellow....It hasn't even stretched straight yet so maybe it will turn green? Any seed I have ever germinated has sprouted green..........any Ideas?

that happened to one of mine, it became green after about 2 days under a light, but the cotyledons sort of shrivelled up a week later the plant looks healthy maybe just a tiny bit over watering, leaves look heavy or idk ill show u later ;/

I've had that happen once, back when I was growing from bagseed. My buddy told me that it was a "sucker plant", and that it'll never take off. He was right, it grew a small taproot, got about the same size as your's, and never got any bigger. It never happened again, so I never looked into it any further. I just assumed that every once in awhile, you'll get a bad seed, genetically screwed.