We have a range of small air-action ornaments to use instead of an airstone or bubble curtain. They are all about the size of a tennis ball and all compatible with the standard airline hose.
Pirate Skull with bandana 75mm x 60mm 80mm approx. Bubbles make mouth open and close
Pirate Skeleton with Gun 75mm x 55mm x 80mm approx. Bubbles come from behind tombstone
Sunken Ship's Cannon 60mm x 45mm x 60mm approx. Bubbles below the cannon
Sammy Sub Submarine 80mm x 60mm x 75mm approx. Bubbles make the propeller spin