black tail tips on male mice

Question
Hi there... we have several male mice in separate cages. We keep them close together so they don't get lonely. There are two of them that are always fighting with one another (from there separate cages). Now the tips of there tails are turning a greenish back color. They are eating, drinking, and behaving very normal. We are not sure what is going on with there tails. Should we be worried? Thank you so much for all of your advice!
Best Regards, Alexis, Ian, and Haley

Answer
Hi Alexis, Ian, and Haley!

Male mice don't need to be near each other, and only need you for company.  Being near other males will cause them to fight (like you saw) and therefore be more stressed than they need to be.  What it sounds like is tail biting - if their tails can reach between the cages the other males will bite them.  If they bite them seriously enough it can cause the tip of the tail to die (turn black) and eventually fall off.  It's an honest mistake (it's happened to me before!), but it needs to be addressed right away.

The sooner you separate the cages the better off they will be - leaving them together longer will just lead to more biting and potentially serious infections.  You'll need to treat all injured tails (even ones with just scratches on them) by cleaning them and applying an antibiotic ointment.  I cannot stress enough how important this is - an open wound is an open door to bacteria that can make your mice very sick or even kill them.  Clean the tail first by adding betadine (found in your local pharmacy or general store) to warm water drop by drop until it is the color of tea.  Then dip a clean cotton swab in the solution and dab it gently over all injured areas and the skin surrounding them.  Leave it for a few seconds, then take a clean swab (dipped in warm water if you like) and clean off what you can.  Don't worry about leaving a little if you can't get it all back off, just get what you can.  Then apply a very small amount of triple antibiotic ointment (like Neosporin) - just enough to cover the area in a very thin film.  If you add too much it's just going to wind up in their tummies, and you want to avoid letting them eat too much of it.

You can repeat cleaning the tails 1-3 times a day until there are NO open wounds left and the black parts of the tail fall off.  Do not try to remove the black part - it will come off when it's ready and there is new skin beneath.

Because open wounds can let in bacteria, it would be a good idea to put all injured mice on an antibiotic.  Tetracycline works on a lot of bacteria, and can be found over-the-counter at your local pet store in the fish section.  It is given in the water bottles (be sure to keep the bottles covered - being exposed to light for more than a few hours deactivates the medicine.  Aluminum foil is a good way to do this).  Here are instructions on how to use it:  http://en.allexperts.com/q/Mice-3824/2010/2/Tetracycline-directions-sneezing-mou...

With proper treatment they should heal up just fine (and have slightly shorter tails)!

Best of luck, and let me know if you have any more questions!
-Tam