Yen Ta Fo, pink-coloured noodle soup

The soup has to be pink-ish for this Yen Ta Fo always. I don't know the meaning of Yen Ta Fo but guess that ta fo is rooted from tofu because that's what made the soup pink.  The red tofu or Chinese cheese (Tao Huu Yee) is pickled with red rice and therefore the color is red.

Kow Lao Yen Ta Fo
The basic ingredients of Yen Ta Fo include the noodle of your choice (Sen - see my post on how to order noodle soup in Thailand here), morning glory (Pak Boong), assorted fish and shrimp balls (Look Chin Pla/Goong), pork (Moo) and cooked blood (Leo-od Moo).  Some places might also add fresh shrimp (Goong), jelly fish (Mang Ka Prune), and white mushroom (Hed Kao).

Sen Mee Yen Ta Fo
You won't find bean sprouts in Yen Ta Fo -- the only vegetables in this type of noodle soup is morning glory.

Few Yen Ta Fo shops will add chili to the soup by default but 90% of the places won't.  The taste for this dish is often sweet and sour which is quite different from other kinds of noodle soup.  I know sweet soup is weird for most people but putting sugar in the noodle soup is quite a common practice for Thais.