Make sure the mouse is at least six weeks old or more.
The code of Practice for the Running of Pet Shops Victoria states
that four weeks is ok for mice to be put up for sale, and so pet
shops may base their advice on this. However mice are barely weaned
at four weeks of age and as such are too young to be away from their
mothers.
Mice come in a "rodent rainbow" of colors and coat types, all
equally as beautiful as the next.
(AMRIS warns against Hairless Mice - as these are genetically
engineered to be extremely susceptible to illness - cancers, colds
and various other viruses. They are a novelty breed and AMRIS
believes an unnecessary breed. Their fragility and inherent genetic
faults makes for short and often unhappy lives in the care of the
general "pet keeping" public. They should therefore NOT be allowed to
be sold in Pet Shops. If you are keen on keeping hairless mice, then
AMRIS recommends you contact Tarron Rodentry - listed above - for
experienced and expert advice)
Choose a mouse with a clean healthy coat, clear wide eyes with
no discharge and one with a clean bottom with no discharge or
staining. Also choose a mouse whose breathing is silent - meaning
no `chattering' or `wheezing' or excessive `sneezing' that may
indicate ill health.
If choosing a childs pet then choose a mouse that can be handled
quite easily without wanting to jump from your hands. Also choose a
mouse that will not try and bite your fingers when you reach into
their cage.
With regular handling in a quiet environment a well cared for
mouse will become tame quite fast.

Boy mouse or girl mouse?
This question is always one of the first for those considering
a mouse or mice as pets.
Well, both are equally as fun to keep. However, before you
purchase either, make sure the pet shop has provided separate housing
in store for males and females.
If not, then you might find yourself in for a nice surprise when
you bring home a pregnant female.
Also, males fighting over females tend to bite each other quite
viciously around the rump and tail.

It is strongly recommended that if you plan to keep male mice that
you house them separately, as they tend to fight. It is possible to
keep brothers together, provided they have never lived separate from
each other. But male mice will fight for territory with new,
introduced males.
Females can, however, get along quite peacefully together and
since mice are colony animals, keeping two is highly recommended.
THINK before you decide to keep males and females together, as
mice breed very quickly and continuously and it is very hard to find
homes for unwanted mice. (Pet shops will often take them - but many
will go as reptile food). Also, if you keep male and female mice in
separate cages, keep them in separate room also, as males will fight
each other if they smell the females in the same room.
Yes, I will not lie, males do have an odor. However, in a
regularly cleaned cage smell should be no problem.
Tarron Rodentry recommends when cleaning cages that they are
rinsed in really hot water as male mice may remark their territory to
mask residual soap smells. AMRIS recommends, for the control of
disease and mites, that mild tea-tress oil can be added to the
initial cleaning water to soak toys, bowls, nesting boxes and to wipe
cages inside and out, then rinse these thoroughly afterwards.