is this an aggressive hiss?

[beccamperr]

i'm allowing my resident cat (1.5yo spayed female) to make brief contact through a gate with my new kitten (3mo spayed female) after a week of sniffing through doors. is the hiss in the video aggressive or just unsure/confused? link:
my resident cat does not seem to care when the door was shut and would sniff and then walk away. when the door was open, she would eat treats in front of the kitten and didn't ever seem fixated. her fur never poofed up either. she slowly approached the gate after finishing her treat and the video is what happened. i shut the door immediately after. should i be worried or does she just seem confused? she's never shown any aggression to anyone before, even strangers and the vets, but hasn't been near a cat since november (she never had issues with the 4 cats she lived with then and there was 0 introduction period with them as they were at a vet tech school).

any advice on introducing them going forward would be helpful!

 

[Kris107]

A lot of cats hiss at new cats until they're sure. I've fostered many kittens, and my cats always start by hissing at their sight. I wouldn't be too worried about it at this stage. Have they interacted through the baby gate yet?

 

[beccamperr]

A lot of cats hiss at new cats until they're sure. I've fostered many kittens, and my cats always start by hissing at their sight. I wouldn't be too worried about it at this stage. Have they interacted through the baby gate yet?

This was their first interaction through the gate! She doesn't hiss if she sees the kitten from a farther distance, only when they're both at the gate.

 

[Kris107]

Yeah, for now I'd say that's just her unsure-ness. What did kitten do?

 

[beccamperr]

Yeah, for now I'd say that's just her unsure-ness. What did kitten do?

Pretty much zero reaction, she actually tried to scale the gate less than 30 seconds later before i shut the door because she's obsessed with playing under my bed haha

 

[susanm9006]

As hisses go it was a pretty mild one so I wouldn’t consider it aggressive, just nervous or fearful to be expected when meeting a strange cat.

 

[Kris107]

Ideally kitten will respect cat boundaries to some degree. I'd worry for if kitten was obsessed with cat. Some kittens can be relentless. Keep us posted!