WordPress jQuery fadeIn, fadeOut not working

When I transfer my static HTML into a WP theme, my fadeIn effect stopped working on navigation buttons for a gallery. They no longer fadeIn/Out, but just pop up instantly.

here the code:

jQuery(document).ready(function($) {
  $("#showcase-nav").hide();
  $("#showcase").hover(function() {
    $("#showcase-nav").fadeIn("slow");
  }, function() {
    $("#showcase-nav").delay(800).fadeOut("slow");
  }
);

html:

        <div id="showcase-wrapper">
            <div id="showcase">
                <div id="showcase-items">
                    <a href="/portfolio/" title="Simona & Sebi - Wedding invitation design" class="active"><img src="/media/selected-simona-sebi.png" alt="Selected work - Simona & Sebi - Wedding invitation design" /></a>
                    <a href="/portfolio/" title="TEMISZ anniversary kit - Visual identity"><img src="/media/selected-temisz-anniversary-kit.png" alt="Selected work - TEMISZ anniversary kit - Visual identity" /></a>
                    <a href="/portfolio/" title="STMF - Visual identity"><img src="/media/selected-stmf-visual-identity.png" alt="Selected work - STMF - Visual identity" /></a>
                    <a href="/portfolio/" title="TEMISZ - Website design and development"><img src="/media/selected-temisz-website.png" alt="Selected work - TEMISZ - Website design and development" /></a>
                </div>
                <div id="showcase-nav">
                    <a href="#" class="goleft">Previous</a>
                    <a href="#" class="goright">Next</a>
                </div>
            </div>
        </div> <!-- END #showcase -->

P.S.: I am using noConflict