Something wrong with my mouse - no idea!

Question
I'm not sure when it started, but my eldest mouse, Kyo, has started to act very strange. Hes been moving in a strange, uncoordinated manner, as if he's got brain damage or something of the sort. he cant climb the bars of his cage (which he used to do -constantly-. now he just climbs up two bars with his front paws and falls off). He's perpetually sniffing around (i think its sniffing...) and moving his head all directions while doing it, and walking very wobbly-like and in random directions, like hes not sure what hes doing. Hes been eating and drinking, though rather clumsily (ive been watching him). And... very unusually... hes not vicious anymore. This mouse previously was very ill-tempered, despite my efforts at handling him well as a young mouse, he became mean when his brother mouse died early on. he used to practically lunge himself at my hand when itd enter the cage unless he was distracted, and now, he barely notices im there, if at all. he even used to gnaw the cage bars in my direction! he cant seem to get his teeth on the bars, though he seems to try.

Though... hes about a year old now, and was purchased as a feeder mouse. the other mouse purchased from the same place the same day died only two months after purchase from unknown cuases, so i suspect some genetic background issues...

Answer
Dear Mali,

If there were no similarities between the two mice's symptoms at death, there is probably no connection.  If I had to guess I'd say brain tumor (or fast-acting brain disease), but veterinary medicine isn't my expertise.  However, luckily there is a medical expert to ask:  The other mouse expert, Cass.  I tried to get her to write in her profile that she has vet experience; anyway, she does.

If it is something like a brain tumor or brain disease, the only thing you will be able to do is try to keep the little mouse comfortable.  Make sure he can easily reach his food and water, and there is nothing he can fall off of. Handle him carefully, because he may not be able to hold on or balance like you expect him to.  

Best of luck.

squeaks,

Natasha