Does it have anything to do with water quality? Do the goldfish knock the leaves off? I'm tryin to landscape my tank with the ludwigia, bacopa, echinodorus', and some java ferns ( and maybe some lobelias) and any tips for their growth?

How much light do you have in your tank? Tell us a little about your tank

Bacopa and ludwigia need fairly high light levels. If you are losing leaves, this could be the problem.

my lihgts are fairly light although I donot know how many watts...? Is there a way I could find out? I Have 2 hoods to my 55 gallon tank, they are at least 20'' long, will that help? sorry

It should say on the ends of the tubes. It sounds like they are 20 watt tubes, though, from the length.