Pond plant identification please.

Dirtymonkey

This grows deep in our pond, grows very quickly.  Was sold to us as bog bean.  Any suggestions please?. 

Asarum

Possibly Lythrum salicaria, Purple Loostrife.  Very invasive for a small pond.

Not bog bean anyway.

Dirtymonkey

Thanks but looking at loostrife leaves I don't think so, from what I can see they're opposite each other.  The leaves on this definitely aren't.   No purple flowers either. 
Any other suggestions?.