My mouse had blood on her :(

Question
I have been asking Natasha a few questions and thought id ask you this so i dint bother her again!!! I have 2 mice and both are sisters, same age same cage etc. ! mouse (call her E) was very fat. I wondered about pregnancy but 3 weeks has passed. E also had breathing problems like really heavy but that has mainly stopped and is usual. 2 nights ago E( i think it was her) was quitly squeaking in her cage but when i checked all was fine. In the morning she had a minor amount of fur loss on her head so i sprayed her with mite killer.

She was squeaking last night but again i checked about 10 times and all was fine but i got her out in the morning (about 30mins ago!) and she had blood on her back.

The blood was not in like a clump or puddle but looked like a spray of blood. When i touch her under her front and back legs she squeaks but has done for a while now. I will take her to a vets if i need to worry and can seperate them. I really need advice as im not at all experianced. Please help and thanx for your time, dems


I will be happy to tell you anything else you need to know :)

Answer
I would assume they are both the same sex as 3 weeks have passed and their have been no babies.

Females have nipples on their bellies and males will have obvious testicles in a relaxed state (when they are nervous they will retract them).

Fighting is fairly common in males especially if they weren't brought up together or if theres not enough food or territory. You don't need to worry about separating them whilst you take him to the vet but theres no harm in taking them together.

Mites are uncommon in mice and are usually introduced by hay or straw. They are also quite obvious if you check the fur especially if they are filled with blood.

I would recommend taking him to the vet and have him checked out in case its something serious. It could be a reaction to the mite spray unless it was specifically for mice.

Please feel free to ask any more questions. I hope E recovers soon.