250 grams is still a baby. he should grow out of it. I bought a pastel once that the breeder didnt even want to take out of the bag because she was a striker, and she was about 300 grams. I named her Grace because of her attitude. Anyway she grew out of it. Like many of my other aggressive babies have. Like most children, he's probably going through a phase.

A small enclosure and some tight hides may make her feel more secure, sounds like defensive strikes which means he is probably nervous/scared.

Is he in a glass tank?