[finnfinnfriend]

Can they be fully submerged? Because I always see them at the top of aquariums with the top sticking out of the water...

 

[Bombalurina]

It depends on the brand of filter. Each one comes with specific instructions that should tell you.

 

[finnfinnfriend]

It depends on the brand of filter. Each one comes with specific instructions that should tell you.

The one I was thinking about was the Marina i25 internal filter. I looked up the instructions online and it has a clip for the side of the aquarium, but it only mentions a minimum water line....