Can I change a lease to "no dogs" on an existing tenant?

[Johann Jells]

Well, among the many problems with my nightmare tenants that came with the purchase of a 4U is they got a dog without asking me. Unfortunately the seller did not give me copies of their lease agreement, I don't know why, but around here often there's no written lease and this is my 3rd purchase and I have no other excuse besides blaming my attorney. Never again. On the other hand I've been a landlord 17 years and never had a problem with a tenant I picked. My normal lease says dogs must have landlord permission. I've never given it yet.

Anyway, I'm going to give them a Notice to Quit to terminate the month to month and give them a new lease with all the unpleasantness I can under the NJ Anti-eviction laws (they require lease renewals and limit rent increases to "not unconscionable"). Can I force a lease change that says "no dogs" on someone with a dog?

Does anyone agree with this opinion, which implies I could even evict them now unless they could show a lease that specifically allows pets:

[quote]If your lease does not state you can have animals in the property you can't. Leases cover what you can do, not the thousands of things you can not. There is no way around it, you have violated the lease and his legal rights by bringing an animal into his property without his consent.[/quote]