There's an extra bracket that needs to be removed in this part. Remove the bracket all the way to the left:
PHP Code:
if($random >= 155 && $random <= 156){
$item = "Green tetra";
$qty = 1;
$newitem = new StockItem($item);
$newitem->append($qty, $mysidia->user->username);
$document->add(new Comment("Oh look! You caught a <img src='http://atrocity.mysidiahost.com/picuploads/png/4181c20e206d7c27063ebd322aeae903.png'/><b>$item</b>! <a href='http://atrocity.mysidiahost.com/exploreforestlake'><b>Continue Fishing?</a></b>", FALSE));
}
}
if($random >= 91 && $random <= 99){
$document->add(new Comment("You didn't catch anything. Better luck next time.", FALSE));
}