Juveniles are piling up. I initially keep them per one to four in small one liter containers, until they are about 1 cm. Then they are transferred to shallow 10 liter trays or larger tanks. Much of what I raise at the moment is on this shelve, some 20 containers. All containers are checked daily, the fish fed, etc. Mortality is very low like this. The room has only mild heating, but I do make sure it’s warm enough for at least a few hours so the fry eat daily. The temperature does not drop below about 14 degrees. The most difficult and precious fry are not here but kept inside a small incubator for their first weeks.