One starts practice at 5:30 a.m. some days, while the other starts a bit later in the morning. One prefers sprints, but the other likes distance. One enjoys pasta with red sauce and venison sausage before competitions; the other loves turkey with gravy and “extra mashed potatoes.”

Sure, Ila and Anna Molettiere have a few differences, besides their ages, but they share a common thing. They’re swimmers – serious swimmers.

“I probably spend about 15 minutes at home every day, when I’m not sleeping,” joked 13-year-old Ila, who started eighth…