Transparent Worms and Fast Beetles in New 150L Pond: Likely Harmless

New 150L pond, banana lily, rocks from ground. Clear worm-like things on pump cord, fast swimming beetles. Asks if harmful to fish (in old pond).

Assessment

Beetles: Likely diving beetles or water scavengers. Harmless unless hundreds (feces toxicity).
Worms: Probably insect larvae (midge, caddisfly) or planaria. Graze biofilm, not fish.

No action needed. Biodiversity indicates a maturing ecosystem.

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