No, not really. They just need a ton of food to grow, but so do any kind of fry. They dont like great currents, just like the adult bettas, so I keep sponge filters in there with them, on a lower setting. They dont like huge water changes also, so smaller ones are in order. And they like warmer water, thats where a heater comes in handy.
Otherwise, food, food, food, thats all they think about. And its kind of cool to see them get their coloring, after they look like grey ugly things for weeks, and slowly get their beautiful colors.
The only thing to watch for is, when they get bigger, as soon as you find aggressive fish among them, take the aggressor out and give him his own little 2 gallon or so container, or tank deviders, or something. They grow up together for a while though, before you see the aggressiveness come out in the males. Mine are around 6-7 weeks old now, and they still are all together...