Here's an example from Google Translate: https://translate.google.com/#zh-CN/en/%E9%B1%BC - you can click on the "Listen" button under 鱼 to hear it pronounced.

In pinyin, 鱼 is yú, but in this case the u is not the same vowel as in 不 (bù). The vowel in 鱼 is actually ü. This sound doesn't really exist in English, but it's close to the sound at beginning of the word "you", without the "oo" sound at the end. To make the sound, you can try saying "yeeee", but instead of having your lips in the normal position, have them pursed as if you're about to make a kiss or make duck lips.

In terms of tone, 鱼 has the rising tone, so it's pronounced with a rise in tone similar to that used in English at the end of a question.

鱼 (yú) is pronounced as "ǘ" (i.e. ü with second tone)! The ü sound may be tricky for English speakers! Round your mouth as you'd say "u", but pose your tongue as you'd say "i"! Be careful, though! It's supposed to be a single sound and you'll probably sound more like "iu" on the first attempts! By the way, you can get the idea of it by doing this: try the "i" sound (as in "me" or "interest"), make it long... while doing this sound, round your mouth! The sound you want is that, at the end!