White amur--also known as grass carp, have been the topic of many discussions on this forum.
They like to eat rooted aquatic vegetation quite a bit. Filamentous algae not so much.
They have short guts and "squeeze" nutrients out of the plants, not really digesting the actual cellulose. Because of this, many nutrients are still available after defacation for promotion of algae blooms. If you were able to account for dry weight of plants before stocking white amur, then subtract dry weight of fish mass created, you would still find that almost all of the mass was available for plant production, just different kinds of plants, such as the dreaded filamentous algae.
They taste really good, in my opinion, but are difficult to capture because of their dietary preferences.
