A pond with a basement makes for a more natural appearance. It serves as sanctuary for the fish to escape predators, hides the pump and other components, and keeps water from stagnating under rocks lying directly on the pond liner.

Rocks placed immediately atop the pond liner, can harbor nasty, potentially toxic muck. Raising the rocks off the liner with a flooring system creates a false bottom. Water flows through these elevated rocks instead of stagnating between them.

Predators hate this system. When bad guys grab a seat at the lunch counter, fish ain’t on the menu. They’ve escaped (most of the time) to the safety of the basement. Problems solved, sort of.

A floor made from elevated rocks also hides the unnatural bits liners, pumps, pipes, prefilters, etc. But, it makes accessing all this apparatus more difficult, especially the prefilter that demands frequent attention.

Enter our heroes, THE FISH. They glide effortlessly through these tight spaces. And, they’re looking for work. In fact, they'll work for food! The patented prefilter you see lets the fish indulge their masticating parts and take over the cleaning chores. “Teaching a fish to fish”, so to speak. It's a symbiotic transaction. The fish are happy for an easy and frequent meal. I’m spared the filthy and frequent drudgery of prefilter maintenance.

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VIDEO AND OTHER COMPONENTS
Video: Two Axis network cameras housed in bespoke waterproof cases.
Lights are IP68 strip LEDs: https://imgur.com/a/2IRyRUY
Rocks rest upon plastic grates, supported by aluminum lintels and PVC posts.
The prefilter is the black/orange/silver device shown in the lower level view. The fish keep it clean and free flowing. For more information, see https://grazenfilter.com