I have one 8 week old female kitten and one almost 9 week old male kitten yesterday. They are both very temperate but when they are introduced to each other, every time they make eye-contact the female hisses at the male. He doesn't like the female hissing so he goes away and hides under something.
Often he will come up to her like he is curious but she just hisses at him. It isn't like full blown hissing but she does the same thing when she's playing with her cat toys and there was no aggression on the car ride home. They were both scared and climbed onto my lap and slept on top of each other facing different directions and slept for the car ride.
All night, the female laid on top of me guarding me from the male. He would meow and if I meowed back he would climb up onto the bed and try and come close, realize she was there, and walk around me on the bed, then go back down to side.
Neither of them are skittish and also both have refused to eat or drink anything since I got them at approximately 6pm yesterday. It is 1pm now and I am getting worried they just want to play and explore.
Should I take them to the vet?
Update: the male just started eating dry food on his own and I managed to get the female to eat some wet food. I am not sure why she was being so picky but she devoured a large amount of it mixed with her dry food around 36hrs after I got her.
To stop them fighting I used there favorite toy on the bed and each time she hissed at him I picked her up immediately and put her on the floor and let it be the other ones turn. At first she seemed to think that the toy belonged to the other cat and not her but eventually she figured out she could play with it as much as she wanted if she didn't hiss at the other kitten. They have been playing and chasing the others tail etc since.