My guinea pig is too skinny?

If I am following your question properly any time you have weight loss in a guinea pig it is a big red flag to a health problem and time to see an exotic vet, it would be a bit difficult to think the same diet would have anything to do with a sudden loss of weight, so please do take your guinea pig to a exotic vet asap. Remember guinea pigs are prey animals and hide the fact they are ill until they are in the acute stage and they can not hide it any longer, and sadly at that point the go down hill and die quickly, I often read of people noticing their guinea pig is ill in the evening and it is dead by the next morning.

If you feed a proper diet your guinea pigs will adjust to a proper weight for their bone structure, if they are not ill. Feed healthy guinea pigs as follows.

Unlimited guinea pig pellets that have 18% protein and a high amount of Vitamin C with no nuts, seeds or other colored stuff in them.

Unlimited hay up to 6 months of age, pregnant or nursing it should be alfalfa, after 6 months of age change to timothy hay, orchard crass or any good grass hay you can find in your local Feed and Seed store.

1/2 to 1 cup of dark green leafy veggies daily such as kale, romaine lettuce, swiss chard, dandelion greens, mustard greens, parsley, red and green bell peppers, a mix of these daily will provide all the fresh vitamin C the need.

Fruit should be fed every 3 days as a treat only as it is to high in sugar to be good for your guinea pig and it is also to high in acid so if fed daily it will cause sores in your guinea pigs mouth.

Change the water daily to assure it is drinking ample water

Some days your guinea pig may eat a lot of hay and not much hay, and other days it may eat a lot of pellets and not a lot of hay, your guinea pig will eat what its body tells it to and by having the food there it can eat what it needs and it will adjust to a healthy weight.Always make sure your guinea pigs are healthy though,

If the fat one is a female and the skinny one is a male she's probably pregnant. If they are both of the same sex then one may be bulling the other from the food. I would allow them to free feed by always giving them more than enough food. If there is no improvement one has worms or some sort of internal parasite. You can get warming medicine at the local pet store to administer to it. Get worming medicine for rabbits and use half the dose.

I like to get little sweet piggy food for mines .

She is really chubby but not to fat and she cant get enough of pig snacks (:

some of my guinea male guinea pigs are skinny but that's just how they are and my female guinea pigs are fat ( they are not pregnant) maybe his teeth are over grown and that's what making him skinny if that's not it go to a vet and if his teeth are over grown u will need to go to a vet anyway or he will die

I think that mabie one is eating the others food. Make them eat seperatly and see how it gos

You need to take it to the vet. Usually when you start to see the wight loss, it is already too late. If it is not eating, you definetly need to take it to the vet.

i think the fat one isnt letting the skinny one eat...make sure you give them more food...