Aquatic weeds often cause serious problems in ponds, interfering with
fishing, boating, swimming, and irrigation. Extremely dense growths of
filamentous algae and submerged weeds may cause serious problems to fish
as a result of night time oxygen depletion.
Manual algae prevention is very labour intensive and not always
practical and the use of chemicals, algaecides, herbicides etc, if not
used in precise doses or under strict supervision by experts, can cause
an imbalance of the natural nutrients in the pond that may have a
negative effect on fish, plants and other species.