Sudden Lethargy and scared behaviour

[Gravitaria]

My male guinea pig suddenly changed behaviour from outgoing, loving attention and being dominant to now staying in pretty much one spot, only eating if I guide him to the bowl and hay with my hand in front of him. I’ve noticed a couple of marks near his face but I’m not sure if they would be the cause. I’m calling the vet for an appointment in the morning but any advice would be greatly appreciated thanks. I don’t know how to add pictures or I’d attach one of said markings

 

[RescueBoyMum]

Hi there. Does he have a friend that he’s maybe been fighting with? Just wondering if bites have caused the markings/made him frightened. Good that you’re going to the vet as it could be something else eg arthritis that’s causing him to stay in one spot. Good luck with your appointment.

 

[Gravitaria]

Hi there. Does he have a friend that he’s maybe been fighting with? Just wondering if bites have caused the markings/made him frightened. Good that you’re going to the vet as it could be something else eg arthritis that’s causing him to stay in one spot. Good luck with your appointment.

He does share a space with another male but any of their minor spats have just had them on opposite ends of the area for a few hours before returning to normal. He’s been this way for just under 48 hours. I only noticed it when I returned home and immediately googled for some help which seemed to point to possibly a loud noise spooking him so I left it for a day as that’s the span of time the post said it should sort itself out within. I’ll be sure to ask the vet to do any checks for arthritis but I’d be surprised since he’s only around 8 months old

 

[Piggies&buns]

I’m sorry to hear this.

Lethargy and reluctance to eat as symptoms would be a first concern of illness, not of being spooked.

Please switch from the routine weekly weight checks and instead weigh him daily (each morning). This is so you can more closely monitor hay intake and enable you to step in with any required syringe feeding more quickly if he is losing weight (50g or more is of concern; 100g in 24-48 hours would be an emergency). Stepping in with syringe feeding where there is weight loss and lack of appetite is urgent to prevent stasis.
If he is not choosing to eat by himself and has been like this for a couple of days then he could already have lost weight so please do read the emergency guides about weight checks and syringe feeding.

Diagnosing and treating any illness always comes first and before any other consideration. However if and when illness is ruled out, I would then look to bond issues rather than being spooked by an external noise. I say this due to the fact you are finding marks on his face. This could mean there are potential bond issues.
Things like cage size (180x60cm), amount of resources and having hides with two exits (single exit hides are a risk of causing fights) are important to boars but if a bond is failing then there is not anything you can do to solve that after the fact.
If they are both around 8 months old then there is a hormone spike at around that age. That spike tends to be less than the one between 4-6 months of age but it can still cause problems in unstable bonds and be the thing that breaks the camels back.
Any fights causing injuries or bullying behaviours (such as preventing him from eating) would mean the bond is failing/has failed and they would have to be permanently separated.
Separated piggies need to be side by side in cages measuring at least 120x60cm (this measurement is the welfare minimum).

I’ve added guides below to help further

I hope he is ok

Emergency and Crisis Care as well as Bridging Care until a Vet Appointment
Weight and Weight Loss Explained: BMI, Weighing, Poos and Feeding Support
All About Syringe Feeding and Medicating Guinea Pigs with Videos and Pictures

Bonds In Trouble

 

[Truffolo]

He does share a space with another male but any of their minor spats have just had them on opposite ends of the area for a few hours before returning to normal. He’s been this way for just under 48 hours. I only noticed it when I returned home and immediately googled for some help which seemed to point to possibly a loud noise spooking him so I left it for a day as that’s the span of time the post said it should sort itself out within. I’ll be sure to ask the vet to do any checks for arthritis but I’d be surprised since he’s only around 8 months old
[/QUOT
If your piggies are having a fur ball fight, they need to be separated immediately unfortunately. They will continue to fight and the risk of bite wounds leading to accesses is dangerously high. It sounds like there has been an injury and your piggy is not happy being in the cage with the other piggy. Once a fight has happened, their bond is broken forever and they cannot share a cage. The cage needs to be divided into two 3x2 foot or bigger cages Fighting will not resolve the hierarchy or establish the pecking order.

 

[Wiebke]

Hi

I am keeping my fingers crossed that your vet can find the cause for the loss of appetite and lethargy. Both are sadly more general symptoms of (serious) illness that can cover a wide area of ground.

Please follow the advice @Piggies&buns has given you. The links contain all the practical how to tips and in-depth advice that we can't repeat in every post.