Hi all, I have about 10 water hyacinth plants in my pond (8ft diameter stock tank) In my research I found many people saying that these were good plants to help filter water and would spread rapidly to provide coverage for my few goldfish. I have noticed that they are growing larger individually but have not spread horizontally at all. I'm wondering why this is? The pond gets probably 4 hours of sun per day. Perhaps it's not peak growing season yet? They have been in the pond for a few months now. Any help is appreciated, thanks.