How to show a custom taxonomy in the theme?

I have created a custom post type: register_post_type() and custom taxonomy: register_taxonomy(), but when trying to show the categories made to the post type in the theme single-{post_type}.php they do not appear.

I am using this but without success:

$categories = get_the_category($post->ID);

foreach($categories as $category){
  echo $category->name;
}