Why does this happen and how??

Question

I got a 1000 gallon outdoor pond full of fish and i got a water fall and this green tank that holds all of the water for the water fall and i open it and look at it and i find these small snails i think idk can some one help me

Answer 1

sounds like you have a great eco system going on

the snails are keeping down the algae  

Answer 2

the manufacturer probably put the snails in there to eat the algae from the tank or something. Snails can actually be very beneficial to an outdoor pond by eating algae and things so i wouldn't worry about it.

Answer 3

it's normal :)  sounds cool though!