Cecil is one of our small trout pond experts. See the photo in this link as testimony of his ability.
http://www.pondboss.com/ubb/ultimatebb.php?ubb=get_topic;f=20;t=002293;p=1#000005 I also question the benefit of introducing submerged vegetation into your trout pond. There are pros and cons to doing this. What do you think the benefits of these weeds would be? We can discuss your ideas.