Why is my new kitten not eating and sleeping after flea treatment?

It's not likely to be a symptom of the fleas but it could be a symptom of the flea treatment you use, some of them can cause a side effect of lethargy and lack of appetite which usually does not last more than 24 hours. if by tomorrow Jax is not better, i would recommend taking him to your vet to get checked and treated.

Please have her assessed urgently by an emergency vet and take the shampoo bottle with you. Small kittens are very sensitive to insecticides and weakness and tremors are common side effects and can progress to seizures

This is probably unrelated to the flea treatment, it could be an infection that Bobby is suffering from. If by tomorrow the symptoms do not improve I strongly recommend taking him back to the vet to get treated.

Poor Shadow! She is very young to be fully immersed in water, it is incredibly stressful and dangerous for young animals. Moreover, dish soap is very bad for their skin and coat and not even a truly effective way of killing fleas, when the eggs hatch there will be no residual activity. In future it would be much kinder and more effective to buy a spot on flea treatment such as frontline. Now as for why she is so poorly: best case scenario is that she has gotten very cold and stressed and her body is temporarily reacting to it. But on the same hand she may have got water in her lungs ( her lungs are tiny so it doesn't take much) and this will make her incredibly sick and is potentially life threatening. You need to get her to a vet asap because if something serious is going on it needs to be treated quickly. Hopefully it is just that she is in a bit of shock. In the mean time keep her warm and comfortable. In future if you need any advice regarding pet care please ask your vet or ask us, we will always help. Best of luck.

Moving into a new home is stressful for a kitten, but it's very concerning that Bamsi hasn't eaten or drank you. Are you sure he's not doing it at night when you are sleeping? If he still hasn't eaten or drank by the morning, take him into a vet immediately.

Poor baby. It sounds to me like he needs additional medical attention. His pain control may not be adequate for his injuries, or he could be developing an infection. I would recommend taking him to an emergency vet clinic tonight to be assessed and his treatment adjusted.

Congrats on your new kitten, but I'm sorry Eloise isn't doing well. Yes, I would be very concerned that she isn't eating. When cats do not eat going on 72 hours, they develop a fatty liver. A fatty liver is fatal without treatment, so anorexia in cats is considered serious. While bringing home a new cat is stressful for the existing cat, it typically does not cause severe lethargy and anorexia. I would be concerned that Eloise is sick, and I would take her into a vet today for a health check. I hope this helps!