“Natural-looking aquarium tunnel hide that sits beneath your sand, perfect for curious fish.”

My wife wanted an under-sand tunnel for her aquarium. A decent one on Amazon runs $14. So naturally I ordered $20 worth of filament and designed my own. 😄

This is the result — a buried tunnel cove that sits beneath your substrate with two chimney openings that poke up through the sand. Fish swim in through the arched entrance, explore the tunnel, and emerge through either chimney. It looks completely natural once buried and costs a fraction of store-bought hides.

• Sizing - 153.25 × 83.68 × 57.83 mm (scalable—feel free to stretch in your slicer to suit your tank)
• Printed solid — 100% infill gaps means no floating. It sinks and stays put 🪨
• Dual chimney openings — fish can enter and exit from multiple points
• Arched tunnel entrance — wide enough for most small to medium fish
• Burial design — meant to be buried in substrate with chimneys exposed above the sand line
• Natural aesthetic — printed in beige PETG it disappears into a sandy substrate beautifully

• Material: PETG recommended for aquarium use — more water resistant than PLA
• Orientation: Print on front edge, to ensure flatness on front
• Supports: Required
• Infill: Print solid or high infill to prevent floating
• As an Amazon Associate I earn from qualifying purchases.
• 🎨 Filament Used: Official Creality PETG 3D Printer Filament - Beige

• Allow the print to cure and rinse thoroughly before placing in your aquarium
• PETG is generally considered more aquarium safe than PLA but is not certified food safe
• Monitor your fish when first introduced to any new decoration

• 👤 Personal Use: Print it, bury it, enjoy watching your fish explore it
• 💼 Commercial License: Want to sell printed aquarium accessories at your local market or aquarium shop? Join the R7Makers Merchant Tier on Thangs for full legal rights to sell physical prints of this and everything in the catalog

👉 JOIN THE R7MAKERS LAB: https://thangs.com/designer/r7Makers/memberships