Prepare the Grow-Out Tank Before Touching a Net
The move starts days before the fish do. Cycle the bigger tank fully, fill it with conditioned water, and bring its temperature and pH in line with the nursery the juveniles are leaving, because young fish tolerate a new layout far better than new water chemistry. Fit filtration that will not pull small fish toward the intake — a sponge filter or a guarded intake — and add plants, caves, or simple cover before the move so arrivals can hide immediately. Run the heater and filter long enough to confirm both hold steady, and test ammonia, nitrite, nitrate, and pH on the morning of the move itself.
Decide Who Moves and in What Order
Move the whole juvenile group together when the grow-out tank is their next shared home, since splitting siblings across two systems for weeks creates two sets of water to manage and can leave the smaller fish behind competitively. If a few juveniles are markedly smaller or carry a healing fin, hold those back in the nursery a little longer rather than sending them into a busier tank. Count the fish before you start and write the number down; a count made calmly at the start prevents a panicked recount later when a juvenile is simply hiding in the new plants.
Catching and Carrying Without the Chase
Lower the nursery water level slightly if it helps, remove tall decor, and guide each juvenile into a submerged cup or a soft fine-mesh net with slow movements rather than pursuing it around the tank. A cup is kinder for very small or long-finned juveniles because the fish stays in water the whole time and fins never press against mesh. Keep a lid or your hand over the container during the short walk between tanks. Work in small groups, pause if the remaining fish are scattering in alarm, and never tip the nursery water into the grow-out tank — carry the fish, leave their old water behind.
Settling Them Into the New Water
Even with matched parameters, give the juveniles a short acclimation: float the container or drip new tank water into it gradually until the water they sit in is largely grow-out water, then release them gently rather than pouring. Keep the tank lights low for the first hours and let the fish find the cover you placed. Offer a small feed later that day once they are exploring, and resist rearranging decor to coax them out. Watch for fish pressed against the filter, hanging at the surface, or isolating in a corner, and test the water that evening and over the next few days as feeding resumes.
The First Week in the Bigger Tank
Feed a touch lightly at first, then return to the growth feeding the juveniles were on, and keep up water checks while the larger filter adjusts to a real bioload arriving all at once. Note which fish claim which areas; juveniles that grew up together usually sort their spacing quickly, but persistent chasing of one smaller fish is a sign it needs the nursery a while longer. Keep the old nursery running until the move has clearly held, so a problem in the new tank has an instant fallback. Coordinating the preparation, the count, and those first-week checks through KinsLe Care Teams keeps every helper working from the same checklist and timestamps each completed step.