How can I claim compensation from the landlord if I find a mouse after renting a house?

If it can be proved that the mouse settled in the room before renting the house, and the landlord knows that he didn't tell you, it can be considered as contracting fault or fraud, and the contract is also revocable! You can ask the landlord to compensate you for your loss. If you find that there are frequent mouse activities, you should ask the landlord to solve them, such as mending the leak in and out of the house or keeping a cat and getting some mousetraps. He also has the obligation to ensure that the house has normal human habitation.

At the same time, according to the relevant provisions of the Contract Law and the principle of good faith, if this situation is beyond the control of both parties and there is no fault, it can be handled through consultation, such as solving the mouse problem, reducing the rent or requesting to terminate the contract because it cannot achieve the purpose of the contract (seriously affecting your life and rest).

Of course, if the landlord has clearly told you before, and the rent is lower than that of similar houses in the same lot, then you have to bear the loss yourself (buy a cat yourself)

I suggest that you negotiate with each other in good faith (the problem is not big, but it can still be solved), otherwise you can cancel the rental contract and find a house yourself (but you may have to compensate for the losses)!