I have no clue what to do, and I need help!

[Fatty@11324]

So, a little bit of a back story. I had two guinea pigs, Fatty and Coco. I had to put Fatty down because of cancer, and Coco got lonely, so I had to get him a buddy.
I saw Pringles on PetFinder.com, and we adopted him back in February because he was already neutered so we thought it would help him be less aggressive. Pringles was born and raised basically in the wild because he is a victim of animal hording, so he has very little people skills.
But now, he has drawn blood from Coco twice, and I can't even hold him because he first chatters, and then he bites, and he will not let go. Coco is always squealing because he is being chased by Pringles.
I have tried to hold him and give him treats, I have tried hidey huts, and hay. Nothing works and I don't know what to do, I swear he hates me and Coco.
Please help!

 

[Piggies&buns]

He doesn’t hate you, but due to his background it sounds as if he is terrified.

As he has drawn blood on Coco then sadly their bond will never work and they need to be separated immediately and permanently.
It will be much better for Pringles to not feel the pressure of having to share a territory with another piggy.
Coco will be happier being away from Pringles also.
Their cages need to be side by side though so they can still interact between the bars only.

Neutering does not calm guinea pigs or make them less aggressive. It works for other animals but not Guinea pigs. It doesn’t change piggy behaviour and it won’t make two piggies get on. All neutering does in guinea pigs is prevent pregnancy.

Another note is that as he is neutered, did he previously live with females? If so, then it makes it harder to bond them with a boar. Going from being with sows to living with another boar is seen as a huge demotion in status and he will not usually take kindly to that.

I would suggest he is likely to need a lot of time and patience if he is to come round to gentle handling. But also acceptance that he may never want to be handled due to his background.

Understanding Prey Animal Instincts, Guinea Pig Whispering and Cuddling Tips

 

[Wiebke]

So, a little bit of a back story. I had two guinea pigs, Fatty and Coco. I had to put Fatty down because of cancer, and Coco got lonely, so I had to get him a buddy.
I saw Pringles on PetFinder.com, and we adopted him back in February because he was already neutered so we thought it would help him be less aggressive. Pringles was born and raised basically in the wild because he is a victim of animal hording, so he has very little people skills.
But now, he has drawn blood from Coco twice, and I can't even hold him because he first chatters, and then he bites, and he will not let go. Coco is always squealing because he is being chased by Pringles.
I have tried to hold him and give him treats, I have tried hidey huts, and hay. Nothing works and I don't know what to do, I swear he hates me and Coco.
Please help!

Hi and welcome

Please keep Coco and Pringles in a divided cage with interaction through the bars. Their bond is not going to work out. Once blood has drawn, the bond has failed and will never get back on track again. The screaming is submission, by the way; not pain.
A Comprehensive Guide to Guinea Pig Boars
Bonding and Interaction: Illustrated social behaviours and bonding dynamics

Unfortunately, your assumption that neutered malesare less aggressive does most emphatically not work for guinea pigs. In guinea pigs, neutering only removes the ability to make babies but nothing more.
Neutered / De-sexed Boars And Neutering Operations: Myths, Facts and Post-op Care

What Pringles is unfortunately, is rather traumatised and overwhelmed; his fear and insecurity come out as overly dominant and agressive behaviour. He is not used to a pet environment. Socialising him is rather a longer commitment but as I know from my own string of adoptees over many years, it can be done; just much more slowly than you would expect. You have to think in months, not weeks.
Here are some links that can help you see things from Pringles perspective, teach you how to understand his still trigger happy prey animal instincts and how to use guinea pig body language to convey important concepts to him instead of having to wait for him to figure out humans.
Arrival in a home from the perspective of pet shop guinea pigs
New Guinea Pigs: How to Best Manage Arrival and Settling In (lots of very practical tips)
Understanding Prey Animal Instincts, Guinea Pig Whispering and Cuddling Tips
A - Z of Guinea Pig Behaviours

Please give him the space and time, patience and persistence that he needs to settle down, realise that he is safe and learn to trust.