you kind of say it as "yuur" and then say 'see' (like, 'I can SEE the stars' kind of 'see'). so altogether is "yuur see." If you don't get the "yuur", it sounds like "bruise" in chinese.
But shouldn't this be in the languages section? This is for fish care, not how to say something related to fish.
Nevertheless, here's your answer.
EDIT: ahaha, Shitake, isn't that a mushroom?
EDIT: sorry, I assumed you wanted cantonese? Or manderin? I can answer correctly in cantonese, but I'm a bit rusty on manderin...
EDIT: umm....I assume you mean "Shiitake," and not the term "Shithead..."
wow, this is off topic from the question.
Anyway, to say fish poo in manderin is...
"yuuhr fun" The last part is not exactly "poo", the manderin language is very formal, so it's something more like "fuhn". "Yuurh" is said more like "Yueehh" and "fuhn" (if you know your pinyin) is the one that is said in the tone like this " \ " (which is, straight down?)