The grow-out move is the nursery's graduation day, and timing it well is a judgement every breeder makes by eye. Move too early and tiny fry vanish into a big tank's filter intakes and feeding competition; too late and crowding quietly taxes growth you never get back. The fry themselves publish the deadline, if you know how to read them.
The Signs That Say the Nursery Is Full
Watch growth spread first. A batch that was uniform begins splitting into a leading group and a trailing group as the boldest monopolise food in limited space — that widening gap is the classic signal. Water tells the same story: if holding quality in the nursery now takes noticeably larger or more frequent changes than it did, the biomass has outgrown the box. Behaviour adds a third vote, with fin-nipping, food-guarding and restless crowding at the surface appearing in species that were peaceful at lower density. Any two of these three together mean the move is due this week, not next.
Prepare the Grow-Out Before Touching a Net
The receiving tank should be cycled, warmed and filled with water matched closely to the nursery's — ideally, base it largely on water from the nursery itself so chemistry arrives unchanged. Cover filter intakes with sponge, set flow gentle, and add some plant cover or structure from the old tank so the new space smells familiar and offers hiding places. Decide the feeding plan for the bigger volume in advance: food disperses differently in a larger tank, and fry that fed from one cloud must now find sprinkles spread across a wider surface. A prepared tank turns moving day into a transfer; an unprepared one turns it into an emergency.
Move Fish Gently and Together
Catch fry with a soft container or jug scooped in the water rather than lifting them through air in a net whenever size allows, and float or drip-acclimate only if the two waters differ more than slightly. Move the whole batch together rather than skimming the biggest, because grading during the move stresses everyone and the hierarchy simply re-forms in the new tank within days. Count as you go — moving day is the one reliable census a breeder ever gets. Dim the lights in the grow-out for the first hours, offer a small feed once the group is exploring, and expect a day of shyness before normal behaviour resumes.
The Fortnight After the Move
Growth after a well-timed move is often startling, especially among the former runts, who were short of food and space rather than potential. This is your second grading window: youngsters still failing in roomy, well-fed conditions have told you something real about themselves. Watch water quality as feeding increases to match the larger quarters, and resist immediately filling the freed nursery space unless its own cycle has been maintained. Recording who netted, who acclimated and who did the first grow-out feed in KinsLe Care Teams, each duty assigned and timestamped, makes your fry's moving day a calm relay instead of a scramble.