Hi. I bought a new tank and have cycled it and have just added a few fancy goldfish. The tank is 24L and came with a filter as its a starter set. I'm currently unsure about the filter and the where the output tube goes. The tube with the black round end on it is just above the water surface and then rest of the filter is below the water level, is this right? I've positioned the filter on the back glass of the tank. Also the fish seem to move around the tank if they get in the bubble stream which is produced from the hole where the water is pumped back out from the filter. Could anyone tell me if the filter they use makes their fish move around alot? And if I need to do anything to adjust it? Thanks!