If you looking for fetch custom post by tags yes is it possible to retrieve post entry for a custom post type by tag, I have been trying with the following code.

<?php
$CurrentTagSlugs = get_queried_object();
$CurrentTagSlug = $CurrentTagSlugs->slug

query_posts( array( 'post_type' => 'video', 'post_status' => 'publish', 'tag_slug__in' => $CurrentTagSlug) );
if ( have_posts() ):
    while ( have_posts() ) : the_post();
    echo "<h2>".the_title()."</h2>";
    endwhile;
endif;
?>