Penn Plax

Penn Plax makes aquarium equipment and accessories across a wide price range, and the piece we carry from them is an old-fashioned one that still does its job.

The Penn Plax undergravel filter sits beneath the substrate and draws water down through the gravel bed, turning the whole bed into a biological filter. It runs on air lifts or on powerheads, depending on how much flow you want.

Undergravel filtration suits keepers of hardy community fish, goldfish and cichlids who prefer a simple system with no cartridges to buy, and it pairs with regular gravel vacuuming. It is not a good match for planted tanks or fine sand. Local pickup available.

Suitable gravel is listed under gravel and substrate.