I created this model to help keep my floating platform in place.  Before there were posts with a suction cup and my turtle kept swimming between them and the aquarium wall and dislodging them.  This is a 3 piece print to hang over my 55G tank and through the platform.  There is a hole in the vertical pieces to allow water in.  The 3 pieces screw together and I printed out 2 of these at a time on the same sheet.  I used PETG.  I painted supports around the male threaded parts only.