Sequels Question about the symbiotes

[spideyman101]

Ok, to kill some time until Spider-Man 4...

Why is it one is black and the other red?

Is it that they are red when they are first born and as they age they get darker and darker until they're black?

Or is it just simply that they are "born" different, kind of like how human's are born different?

 

[Venom 1988]

The reason why the other symbiotes (Carnage, Toxin, Scream, etc..) are different colors is because they were spawned on earth, so the atmosphere has a different effect on them. There basically "mutant" symbiotes if you will. Thats also the reason why they have different powers and characteristics.