I finally found:

net size/abw for tilapia fingerlings
Net mesh sizes for tilapia fingerlings are selected based on the desired size of fish to be harvested. Here's a breakdown:
Average Body Weight (ABW) and Corresponding Net Mesh Sizes:
1-gram fry: Can be reared in 1/4-inch mesh cages to produce 10-gram fingerlings.
10-gram fingerlings: Can be restocked into 1/2-inch mesh cages to produce 25- to 30-gram fingerlings.
25- to 30-gram fingerlings: Can be restocked at different densities to produce 50- to 60-gram or 100-gram fingerlings.
3-5g fingerlings: Stocked at 20-25 per cubic meter in net cages.
8-9g fingerlings: Average weight for 3-inch fingerlings.
20-35 grams: Tilapia fingerlings can reach this average weight in two-three weeks.
25g: A 4-inch fingerling can weigh this much.
10g - 150g: General weight range for fingerlings.
60 to 100 grams: Overwintered, 1-year-old fingerlings are often used to produce fish of 1 pound or greater in cages.
Mesh sizes ranging from 6 to 12 mm: Used for continuous partial harvesting of fingerlings, depending on the desired size.
Important Considerations:
Smaller mesh sizes: Essential for retaining smaller fish and eggs, especially for preventing reproduction in cage culture. Reproduction can occur in cages with 1/10-inch mesh or less.
Mesh size and fish girth: When using a gill net, the mesh size should be about a quarter smaller than the fish girth to effectively catch fish.
Different net types: Various net types, including hapas and production net cages, utilize specific mesh sizes tailored to different stages of tilapia development and intended purposes.
Feeding rings: Small-mesh screens (1/8 inch or less) are used in feeding rings to retain floating feed and minimize waste in smaller cages.
Average Body Weight (ABW): Calculated by sampling a group of fingerlings and dividing their total weight by the number of fish.


My 3mm X 3mm net should have held them, perhaps they are holding near the bottom of the net, under the algae & weeds I put in the cage, or there is a hole I don't know about. If they are still in the cage they should be about 1-1/4 " now. If not then they were CNBG hors d'oeuvres.