Can't say for sure, but the ones I get from Hamilton Bait and Tackle will grow if I let them. Just got to feed them. Magic Worm food is great but I use a home made mixture cormeal, oatmeal, egg shells and any leafy greens I can steal from the kitchen.

Most worms reproduce prolifically and reach maturity in 3-4 months, The European worms grow and really grow fast when conditions are right and typically are a bit larger than red wigglers.