Yeah, you definitely should be honest and up front.
The landlords are usually pretty good about writing up the lease and will typically have it in writing that any pets are a violation of the lease and grounds for eviction. And even if it didn't lead to eviction, I'm guessing it would be an uncomfortable living situation if the landlord found out he/she was being lied to.
Good luck with your search!! I'm sure it's stressful, but you'll find something.