Modular Grotto Observation Cave | Build-Your-Own Aquarium & Terrarium

Build your own hideaway for aquariums or terrariums. We created the Modular Grotto as a flexible canvas for aquascapers. Clip extensions, entrances and columns together with the included clips and dowels to form tunnels, arches or sprawling cave networks. The system scales from tiny shrimp to chunky plecos, and we’ll keep releasing new module shapes so your design options can grow right alongside your critters.

⭐ Features

• Full-view frontage – open face sits flush against the glass for an unobstructed look at your critters while keeping their retreat dark and safe
• Mix & match pieces – combine 5 cm, 10 cm or 15 cm extensions with column or entrance modules to create any layout
• Adjust in seconds – add or remove sections to suit your scape or expanding critter family
• Secure clip-and-dowel connectors – snap modules together firmly, no glue needed
• Aqua & Terra versions – aquarium modules are printed denser so they sink; terrarium modules share the same look at a lighter weight
• Durable PETG – strong, aquarium-safe plastic that rinses clean

📦 What’s included

• Your selected module(s) – each sold individually so you only buy what you need
• Clip and dowel set for each module

📐 Approximate sizes (L × W × H)

• 5 cm Extension – 5 × 12.9 × 10.7 cm (2.0 × 5.1 × 4.2 in)
• 10 cm Extension – 10 × 12.9 × 10.7 cm (3.9 × 5.1 × 4.2 in)
• 15 cm Extension – 15 × 12.9 × 11.5 cm (5.9 × 5.1 × 4.5 in)
• Column / Side-Entrance Modules – 10 × 12.9 × 10.7 cm (3.9 × 5.1 × 4.2 in)
• Left / Right Entrance Modules – 15 × 12.9 × 10.7 cm (5.9 × 5.1 × 4.2 in)

🎨 Colors

Available in Black, White, Grey, Beige and Brown. Message us for custom colours.