2 male hermit crab problems?

[Wade]

I've had a male hermit crab for 8 years now and i have just recently gotten a new one, thinking he'd be lonely. The new one is a little smaller than the original one and is also male. Once I got him home and put him in the tank, my larger one immediately started looking aggressive. It went like this... Put him in the tank. Bigger one came up and started checking him out. 5 or 6 seconds, the bigger one jumped onto the smaller one and stayed there. 3-4 minutes later, bigger one turns new one over onto his back and i pull him off. they seemed fine for the next 5-6 hours, checking them hourly, until i checked them for the last time. The bigger one was once again on top of the upside down new one and beating him up. he was bleeding. I pulled them apart but the bigger one was grabbing hold of one of the other one's legs.

Is this normal? have I kept the other one alone for too long and now he cant be put with another one? is it that they're both male? If you could please give me your input it would be greatly appreciated. Thank you.