Lost rent bc of fleas after tenant moves to another unit

[Brendan Moore]

I allowed a tenant(1) to move into a another unit after a former tenant(2) moved out. Fleas were discovered in the unit tenant(1) moved out of a couple of days after the inspection. Tenant(1) was told to take care of the problem and tenant(1) said he bombed the unit soon there after. A week later the unit was inspected and the fleas are still present. I havent been able to show the unit or have the unit painted as planned. It is nearing the end of the month so I will probably go a month without getting the unit rented out because of this problem. I read through the contract and it doesn't say anything specific on this type of situation. I realize I should of had it professioinally taken care of initially and charged tenant(1) the fee which I will do now. What can I do legally for lost rent since the unit is not in a livable condition? Any information would be greatly appreciated. Thanks!