no they are where water down to the filter,(the name of the filter is Wet Dry) the filter is bottom of the aquarium and then a pump push the water to the to of aquarium and then like that all time, if you see those black objects how you said

has many hole and all that water past over it in the meddle and on the top too and then to the filter, anyway you have to see in internet to that installation, I thing that filter system the most modern and the best quality to filter the water. well I'll hope you find it or building you self. thank for the comment and take care you fish.