Start by Mapping Sight Lines From the Front Glass
Equipment only needs hiding from where people actually look, which is almost always the front glass and slightly above it. Sit where you sit to watch the tank and note what your eye catches: the heater tube, the filter intake, the green or grey plastic that clashes with everything. Corners are the natural hiding places because the side glass already darkens them with reflections — a heater standing in a back corner is half-hidden before you plant a single stem.
Plants That Screen Without Suffocating Flow
Tall, narrow plants make the best curtains because they occupy the sight line but not the water column. Vallisneria spirals up a corner like a ribbon and hides a heater beautifully; tall stem plants bunched along the back wall screen filter intakes; java fern tied to a piece of wood gives a mid-height screen you can position exactly. Plant the screen a little way in front of the equipment rather than against it — a heater wrapped tight in leaves gets hot spots and inaccurate thermostat readings, and a filter intake choked with foliage stops filtering.
Hardscape as a Curtain
Where plants are too slow or the tank is unplanted, wood and rock do the hiding. A branching piece of driftwood stood in front of an intake pipe breaks its straight line into something the eye reads as scenery, and a low rock wall along the back hides the bottom of a heater and the join of a filter. Sloping the substrate higher at the back lifts the whole scape and lets the front planting hide what stands behind it. An unbroken dark background film on the back glass is the cheapest trick of all: black equipment against a black background simply vanishes.
Cables, Tubes and the Bits People Forget
Most nearly-hidden setups fail on the run of cable from tank to socket. Route cables straight down behind the stand in a bundle, keep the filter's inlet and outlet pipes tight into the corners, and if your filter allows external pipework, run it along behind the background film's edge. A spray bar along the back wall under the surface is far less visible than a nozzle mid-tank. Even the thermometer can move to a side pane near the back, readable when you want it and invisible when you don't.
Leave Yourself a Maintenance Corridor
Every hidden heater still needs lifting out and every filter needs opening, so design the escape route before you plant the screen: keep one hand-width of clear water behind the planting, choose screens you can part like curtains, and never cement hardscape over the filter's exit path. Test your design by removing the filter once before the plants grow in — the day something fails is the worst day to discover it is landscaped in. Put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library.