What's This Filter Thing?

[Neon.Tetra]

Friend offered a thing thats not a filter, but disturbs the water. Fits like a filter on the side of the tank. But doesn't filter.
What is it?

Should I get one for my betta tank? I know they don't like surface water movement but has anyone ever heard of one of these before?

ty

 

[fishlover500]

Is it possibly a powerhead? I wouldn't recommend for bettas

 

[ReMz]

probably a powerhead.

There is no reason to have one with a betta, as they are used to help oxygenate the water. As you probably know, bettas are surface breathers. You would only cause stress by creating an unnecessary current.