I have a nano tank I am building, and floating plants on the way I want to keep corraled once they arrive. Worked up a quick feeder ring in Fusion360, checked to see if it'd float and stay watertight and all is well.

Printed in clear PETG, 5% gyroid infill, .2 layer height, 3 walls.

Trimmed off a few strands and gave it a quick heat gun for good measure (to make the texture nicer).