"You eat fish."
The regular u sound as found in, for example, wu 五 cannot follow a Y, that's why it's not spelt with the two dots here. The reason for this is that wu and yu represent a lack of initial consonant for u and ü respectively, so there is no confusion possible. The two dots do need to be used when ambiguity is possible, such as with nü 女
Actually "yu" is pronounced "ü", not "iü"! The "y" doesn't have an "i" sound, it's a marker used for both "i" and "ü" indicating the absence of initial! For example:
月 (yuè) is pronounced üè.
元 (yuán) is pronounced as üán.
要 (yào) is pronounced iào.
英语 (Yīngyǔ) is pronounced īng'ǚ.
The same is true for "wu", there's no "w" sound, it just marks the absence of initial for "u", so:
我 (wǒ) is pronounced uǒ
物理 (wùlǐ) is pronounced ùlǐ.
下午 (xiàwǔ) is pronounced xià'ǔ.
Why is there no audio playback on these pages? It's incredibly aggravatingn, I've reported this feature missing months ago and it's still not working. It's so important for Chinese in particular because the characters don't notate the tones...without playback there is no way for us to know how this is pronounced without consulting external sources.
VERY BAD USER EXPERIENCE 0/10 WOULD NOT RECOMMEND.