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Joan, Vet Technician
Category: Pet
Satisfied Customers: 18342
Experience:  Vet Tech for 35+yrs. Small Animals and Fish
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i have four ( 2 Albino & 2 white ) mice in two cages that are

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i have four ( 2 Albino & 2 white ) mice in two cages that are connected, i noticed that my two oldest mice, Kari and Denna (albino) both have blood on their backs. My other two mice (white) are Fleece and Rue. Kari and Denna have gotten along since i first introduced them together, at about 3 weeks. about 2-3 weeks later i got Fleece and Rue from petsmart as sisters. The introduction was rocky and took a while. They often have squabbles (usually Denna getting after Fleece), but never any blood. Since I noticed the blood I have been watching them and they have both cleaned themselves and have isolated themselves. I have not heard them squeak since and I don't know what to do. Please help.



I am so sorry you are having these problems.

Can all the mice get together at one time, or are they separate where the two pair are separated?

Are they grooming each other?

Do you actually see any wounds on their backs?

Could they have gotten caught on something in thier cage?


Customer: replied 4 years ago.

Thank you for the quick response. They can get all together and a lot of the time they sleep together. Fleece likes to sleep separately around 1/4 of the time. They groom each other a bit. not a considerable amount since I got Rue and Fleece, Rue groomed three spots on Kari. Kari had an infection and Rue opened the wounds. I put antibiotic I got from the vet on it and she has been much better with the fur almost completely grown back since. I cannot see the wounds on their backs but i can see them on their tails, there is a quite a bit of dried blood on Kari and a bit on Denna. I don't think they could have gotten caught on anything they have never had a problem with it before. also the other two mice seem completely fine.


Thank-you for the information. At this point I would separate them into two pair with a divider. Since Kari and Denna seem to get along well, we want them isolated away from the two that are having issues. This way we can see what is actually happening. I would like you to try leave Kari and Rue together and monitor them for aggression. We want to know who is the aggressor, so eventually the one causing the problem can be separated or culled from the group and the other three can live together with no problem. We do need to treat any wounds that are there, since we do not want any infection. You can clean the areas that are bleeding with some diluted Betadine and water as a disinfectant. Once that is done you can use some of the Antibiotic that the Vet had given you or you can use some plain Neosporin on the wounds.

Please make sure that the bedding you are using is not Cedar or Pine, since they are toxic and can cause self mutilation, skin problems as well as respiratory issues in small pocket pets.

I would like to make sure that you have plenty of toys for the two that seem aggessive with each other. If we can keep them active it may help with the aggression. Unfortunately Female mice can get territorial even if they have been together for a while. An agressive territorial female will hump another. I am hoping that toys and space without have all four together may resolve some of the agression issues. There is one other trick that may help which is taking a drop of only Pure Vanilla Extract and put a drop on each chin and rear of

Kari and Rue to make them smell the same. This may help with the aggression since they will smell alike. If that does not work, the final solution will be to separate the aggressive mouse into its own cage. I hope that we can resolve the problem where they can all live together. Please let me know if you have further questions. My goal is to give you 100% Excellent service. Joan

Customer: replied 4 years ago.

so which do i do first separate kari and Denna from Rue and Fleece? Should I just put them into the separate cages close to each other so they can see each other? Rue has never really shown aggression. I would really rather not cull any mouse, or have one alone especially when Rue and Fleece are sisters. I am almost sure that Fleece is the aggressor. when I first introduced them Fleece attack them nonstop, It was when I put Fleece in the unfamiliar cage with Kari and Denna that she became the one being picked on. I made sure they only have white paper bedding. what toys should i get? right now they have 4 wheels, chewing blocks, tubes, and a grass hut.


We are going to separate into two pair. One pair in each cage. Since Kari and Denna get a long with no problems, they are fine together.

Fleece and Rue are the ones we will need to watch, since those two are the ones that have the injuries. We need to see if one is being the dominent female and humping the other(which can account for what looks like blood may be Porphyrin or why they area showing injuries. This sometimes can amount to what is called baberbering where they overgroom each other. If we find that they get along fine, then what I would do is keep the two pair separated. A Pair in each cage.

This is a great activity toy: or this toy:

If we start seeing aggression we can try using the Pure Vanilla Extract a little dab on the chin of each girl and a little dab on the rear. This will give them the same scent and hopefully stop te agressive action. I am hoping it may just be a territorial issue with 4 in one big cage and if we just have two pair separated it may solve the problems. Joan

Customer: replied 4 years ago.

it's Fleece she started chasing the Kari and Denna around the second they got close to her. How much betadine and how much water do i use


Fleece is trying to be the dominent female. Try using the Pure Vanilla Extract and see if that may help. As far as the Betadine and water make the solution a light tea color. I use the color to judge. It is too strong full strength, so using the water to dilute to tea color will work great. Then you can you can use the antibiotic cream or the Plain Neosporin. WE want to be sure the tails heal and not get infected. You are a great parent, but sometimes this behavior happens and it is not uncommon. Joan

Customer: replied 4 years ago.

okay ill separate them for the night and try the vanilla tomorrow. how do i apply the betadine?

you've been such a great help

Hi ,

You can apply the Betadin solution with a Q-tip, cotton ball or a gauze pad to make sure that it is well covered. This can be repeated 3-4 times a day. I hope we can get the aggressiveness under control. As I said this is a common problem and hopefully we can correct it. Joan

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Customer: replied 4 years ago.

i am having a hard time getting the vanilla on them as they are not tame. any suggestions?


Customer: replied 4 years ago.

i identically put the betadine on them all instead of the vanilla. they all started fighting each other when i put the cages together. I have them separated back out now and they seem agitated, shaking their tails, and swipe if the other gets too close. what do i do?


Customer: replied 4 years ago.

now they have stopped swiping at each other but are guarded.


The Betadine was to only treat the injuries on the tails and not meant to be put on all the Mice. Once the area was cleaned with the Betadine, you need to use a little plain Neosporin to heal the areas on the injuries on the tails. The Vanilla was supposed to be dabbed and applied to only two of the mice that were fighting. They have scent glands under the chin and on the lower back and what we are trying to do is make them have the same scent where they will accept each other.

We can try something else. I assumed they were tame and you were able to handle them. I would keep the cages separate and let them settle. Once they have calmed down, at that point gradually bring the cages closer together until they can have the cages next to each other and watch the behavior. We want to do things gradually and try to reintroduce the mice. Please let me know how they are doing.

Customer: replied 4 years ago.

thank you, the cups got switched that had the betadine and vanillia i didn't realize until after they started fighting. Kari and Denna are tame but not Fleece who is extremely skittish and Rue who is usually hiding. they are all getting along well enough now. Kari and Denna are sleeping. Rue and Fleece are just sitting around acting unusual but I think the storm might have them stressed out.


I would start using little treats to handle them more, so if something like this happens again you cna get more control and treat the wounds more easily. Great Job! Joan

Customer: replied 4 years ago.

thank you so much, I hope they can all get along together but i have my doubts.


Like with any animal there will be squabbles, but if it comes to injuries, then you may have to take more drastic action in separating them again. Joan