Why Cannibalism Happens
Within any spawn, some fry grow 2x faster than others. After week 3, the largest fry can physically swallow the smallest.
Cannibalism rates can reach 30 to 50% in cichlid, arowana, and gourami spawns without sorting.
Sorting Schedule
Week 3 — first sort into large, medium, small groups.
Week 6 — second sort. By now size differences are significant.
Week 10+ — monthly grading for species kept long term.
Cheap Separator Tanks
10 gallon tanks with sponge filters work as grow-out tanks.
Plastic storage bins (shoebox size) with a sponge filter work for the smallest groups.
Keep tanks in a rack with one shared heater circulating to save on heating costs.