Seedling weird colours, whats wrong with it?

Completely natural and of no concern. I have been growing plants for 35+ years and the red stem is fairly common. The cotyledons/baby leaves will open soon enough, but transplanting the seedling from the old can might be troublesome. Your seedlings are at their most vulnerable and also at the most important stage of life, as what happens in the earliest days will determine the entire future health of your plant. Starting them in old tin cans is probably not the best way to enter into this world. Plastic pots are cheap and if looked after, will last many years. And while I am giving you a hard time about the tin can, if asking questions in the future, your photography skills will need a bit of practice! You do however get bonus points for taking them in normal light! Hope this helps,....... Organoman.