LED string cololr different to single LED

I recently purchased some 5mm turquoise colored LEDs that when checking them singularly they are the turquoise color i want them to be but now that I've strung them all together they appear more greenish. Any ideas on how to get them back to their original color? I haven't hooked up a resistor to them yet and they connected to a 9 volt battery

9 volt batteries don't put out enough current to run an LED string properly. You want a different power solution. Li-ion is ideal, but AA alkalines will do the job.

Ok thankyou ill do that and see how it goes