Brook Trout Eggs are Hatching

We popped newly hatched alevins onto out classroom digital projector, at Northeast Elementary. 

Brook trout eggs are about 4mm in diameter, while newly hatched alevins are about 9mm in length.  How does that alevin fit into that egg?? 

Do The Math:  The internal (inside the eggshell) diameter of the eggs is probably about 3mm.  Calculate the circumference of that internal space by multiplying the 3mm diameter by Pi (3.14).  You get just over 9mm!