The safest way to do that is to use bio-friendly methods such as filtering or UV rays because these kill the algae but inflicts no harm to the fishes or any sea creature you have there.
You can also opt for chemical methods but I wouldn't strongly recommend this because it can harm the water ecosystem. Yes, they can be more effective in eliminating algae from your pond but the side effects may be devastating.
Generally you should remove the majority of green or red algae in a pond, for it could cause some serious problems. But if you have any algae eating fish (such as catfish), then the pond may be okay
Algae covered the top of the pond. The pond was full of algae.
Yes, it is because without any algae some living animals in the pond would die. Algae can be food for some creatures in the pond. If your pond is just for admiring and not for living creatures, no, it isn't because the algae will take over the pond and no living creature is in it to eat the algae.
Snails and tadpoles
algae
you kill the algae
No
algae
The algae will reduce both air and light causing the organisms in the pond to die.
Pond weed is a weed that grows on the bottom of ponds.
the plants at the bottom of the pond cannot photosynthesize and die as the floating plants are blocking the sunlight from reaching the plants at the bottom.the whole community of organisms there will be affected.
snails