Why did my 5-month-old kitten stop playing, even roughhousing?

That is unusual. It may be that he’s just growing out of the playful kitten stage. As long as he’s healthy and you’ve had him examined then I would just give him time. If there is something medically wrong you should see a specific problem if it worsens. He could just be tired or sore if he had a mild injury you didn’t see. Hopefully with rest and time he’ll be back to his playful self. Thanks for using Petco Pet Education Center, formerly Petcoach to help you care for Hachiko.

Hello and thank you for contacting Petco Pet Education Center, formerly Petcoach. Lethargy and low energy level in such a young kitten is always a concern. This behaviour could be due to fever, pain, intestinal worms and more. Please de-worm your kittens if they have not been dewormed in the last few days. If it does not make any difference, please take him to your local vets for an appointment.

Young kittens should be playful and active and generally don't grow out of this phase until over 12months. I recommend a full vet check to rule out any underlying medical conditions or pain resulting in the lethargy and weakness

It's very hard to know what is wrong based on these very general symptoms, I would expect a kitten this age to want to play all the time so you are right to be worried, my recommendation would be to have him checked by your vet ASAP

These are certainly concerning behaviors for your young kitten. I would be suspicious of intestinal parasites causing the problem, especially if he/she has not yet been wormed. I would recommend taking your cat in to the vet to be checked out and make sure nothing too serious is going on. Hopefully it is something simple like parasites that can be treated easily. Best of luck!

Usually kittens are rather playful at this age, but occasionally some are not very playful. It's good to check that she's not unhealthy though, because this can cause a decrease in activity. Check her gums - see if they are pink or white. If they are white, then he may have anemia. Check the belly - see if it's tucked in or is it round and distended. If it's round and distended, then he may have worms or other intestinal diseases. Most kittens get worms from their mothers, so if he has never had deworming medication, then it would be good to do this. Make sure he is eating and drinking well. Also make sure he doesn't have diarrhea or vomiting. These things can indicate that there is a disease causing him to be less active. The best thing you can do is have a veterinarian take a look at him. They will be able to tell if there is something wrong with him. I hope this helps.

For sure - this is definitely not normal behavior; as you have said before Cutie is normally playful and active. Unfortunately lethargy is a very general sign of many diseases, and it's unlikely that we will determine the cause of her signs or what to do about this here. I would definitely say that you should be worried, as this has been going on for a few days. Cutie needs to be seen by your vet for an examination and likely some testing, including blood work and possibly x-rays, depending on what other symptoms there are (fever, pain, for example) and the results of the physical exam.