Guppy fry survive their first weeks by being almost invisible: tiny, translucent, and tucked into cover while bigger mouths patrol the open water. A gravel vacuum works directly against that survival plan — it stirs the bottom, clouds the water, and pulls a strong current through exactly the low, sheltered spots fry choose. Cleaning a fry tank is therefore less about technique with the siphon than about deciding, before the tube goes in, which parts of the tank will not be touched at all, and then working the rest slowly enough for the fry to do their part.
Where Guppy Fry Actually Hide
New guppy fry split their time between two refuges: hovering near the surface, often under floating leaves, and hiding down in the plants, deep in the planted corners where stems and leaves break up sightlines and current. They do not hide in open gravel, because open gravel offers nothing to hide behind. That behavior is the cleaning map. The planted corners are not dirty corners to catch up on later; they are the nursery, and they stay unvacuumed while fry are small, even though debris collects there. Detritus in the plants breaks down slowly and the plants use some of it; the cost of a few undisturbed corners is small, while the cost of vacuuming them is measured in fry. As the fry grow bolder and spend more time in open water, the refuge corners can be cleaned gently in rotation, one corner on a later clean, never all of them at once.
Hovering the Open Gravel
Clean the open gravel by hovering: hold the siphon tube just above the surface of the gravel and move it slowly across one section at a time, letting the current lift loose debris without churning the bed or starting a stampede. Deep plunging is for tanks without fry; here it digs craters, buries plant roots, and creates the clouds fry get lost in. Keep one hand on the tube ready to pinch it — pinching narrows the tube, cuts the suction at once, and is the brake you use when a fry drifts toward the intake, when the tube nears a plant edge, or when debris needs settling time. Work in sections with pauses between them, so the water stays clear enough to see where the fry are, and pair the vacuum with the regular partial water change so the tank is disturbed once, thoroughly and gently, rather than twice.
The Bucket Check, and Shared Duties
The last safeguard happens at the bucket, because some fry are almost always drawn in despite careful hovering, riding the current while too small and too transparent to spot mid-clean. Before the bucket is emptied, let it stand a minute, then look along its surface and sides against the light for the flicker of tiny fish, and lift any found out with a soft net or a cup and return them to the tank. Emptying an unchecked bucket is where careful cleaning quietly loses the fish it saved, so the check is never skipped even when the clean has run long and the water looks clear. In a household tank these duties are split through KinsLe's Care Teams, so one named person vacuums the open sections and another owns the bucket check before anything is poured away, with the refuge corners written into the shared notes so a helper never helpfully deep-cleans them. With corners left alone by agreement, the Care Teams arrangement on KinsLe keeps refuge planting intact while open gravel still gets cleaned.