Choose the function first. A fountain moves water for display; an aerator pushes air through stones. Their figures are not directly comparable.
Three useful categories
AISITIN 6.5 W fountain
Best for: a compact decorative spray with battery support.
Evidence: Amazon UK listing. Confirm the current listing before purchase.
POPOSOAP 8 W solar pump
Best for: a small water feature where the claimed flow suits the scale.
Evidence: Amazon UK listing. Confirm the current listing before purchase.
Biling solar oxygenator
Best for: supplementary off-grid aeration rather than filtration.
Evidence: Amazon UK listing. Confirm the current listing before purchase.
Affiliate disclosure: as an Amazon Associate I earn from qualifying purchases.
Battery backup has limits
Shade, panel angle, season and cloud cover alter the energy budget. Battery capacity in mAh is not a reliable runtime promise without voltage, load and control behaviour.
Use reliable power for critical life support
Treat small solar devices as supplementary when stocked fish depend on continuous filtration or aeration.