Help! New Kitten!

I recently got a new kitten and brought it to my other cat at home. Whenever my cat Salem would see the kitten or even smell something where he has been, he hisses. There is hardly any hissing now but they constantly fight with eachother and my cat is de-clawed but my kitten isn't. Someone please help me, I don't like to see them fighting like this.
Also, my cat seems depressed because he whines whever someone in my family holds him and won't play with any of his toys anymore and acts isolated to us.

and if it helps, they are both males.

This is normal for a new addition to the household. It needs time. People often recommend a newcommber be placed in a seperate room where they can smell each other and play footsies under the door but not interact directly. You can rub them down with a towel and leave the towel on the other side of the door so each can get used to the smells. Over a couple weeks then let the new cat out and see if things improve. Right now the kitten is probably scared to death and is withdrawing. I'd give him his own space. I take it your older cat is neutered?

Neutered males (or whole kittens) should get along even better than femals would. But this won't happen overnight.

Its taken months for our cat Autumn to acknowledge our 2 kittens. She now plays with them for the first time since we brought them in about 6 months ago. It just takes patience.

When you introduce them for the first time give them their favorite treats. When they smell each other through the door give them a treat. You can even give them their food next to the door for positive reinforcement for getting along, even if seperated.

Thanks for all the help!
And yes my older cat is neutered.
We have no idea if the kitten is, because he was a stray we found at a gas-station about to get hit by a car.
He looked pretty well kept when we took him in and he is very friendly too.
We are thinking he might of just ran away or was abandoned

In that case he might have had a traumatizing experience before you got him. He might just need some down time with no worries and stress. You can easily tell if a male is neutered as they either have testicles or they don't. As long as you get him neutered while he's still young he should be fine learning how to fit into the household, its nota problem unless they are older.

If he whines when he's held and doesn't play, it's possible he has some unseen injury. Have you seen a vet? It might be a good idea to have him checked out.

I think it would be a good idea to have him vet-checked anyway since you picked him up as a stray he may have something he could pass on to your other cat, like worms, ringworm, etc.

The vet will also be able to tell you if he is neutered.

Also you should have one litter box for each of the cats at least and some folks say an extra one also.

Be patient and take your time introducing them and I'm sure they'll be fine.

ditto on the vet check