This is how a (fresh water clams) adult size that you need to know

[Meyer Jordan]

So, It is still safe to add them to filtration system?

If one is vigilant as to the source of these bivalves. They can harbor pathogenic organisms just as any fish or plant. Always utilize a reliable, responsible and established supplier. Sites such as Craig's list and Ebay should be avoided.

 

[Giovanni Carlo Bagayas]

Agree

It would take a sizeable population of any freshwater bivalve to noticeably affect the water clarity on the typical garden pond. Notice the number of clams in the small aquarium in the video. Multiply this by the capacity (gallons) of your pond.
This is not to say that they would not be a welcome addition to the overall diversity of a pond.

Agreed, thanks for noticing.

 

[Rajesh]

Short time lapse video, showing clams filtering water.

Why I have a feeling that it has been tampered/edited video not the original?

 

[Giovanni Carlo Bagayas]

Why I have a feeling that it has been tampered/edited video not the original?

maybe your right Rajesh