Snake in pool

Question
I have a friend who found a tiny snake in a pool. Worried about the chlorine they took it out, after getting it out they relized the snake had such a small mouth it couldn't bite so they kept it. They have had it for 4-5 months now and still aren't sure what species it is. It has a little yellow diamond on the back of its head. It's head is a dark brown and its body is a grayish brown(really lite brown)Its body also has a couple strips down it 2 a dark brown and 2 yellow with the 2 brown close together and the yellow next to each brown could please help me.

Answer
Lauryn,

I would be more than happy to help you determine what type of snake your friend has, but I am going to need a little more information from you:

1)  I need to know where your friend lives so I can determine what species of snake live in that area.  

2)  I also would like to have an approximate length on the snake.  This will make identifying it much easier.

Just out of curiosity, what is your friend feeding the snake?

If you could please respond to me with this information, I would be more than happy to help you identify the snake.

Best of luck,
Joseph Glenn