Stay under market if you have a undesirable property otherwise why would you supplement your tenants rent.

Not only to keep them from being aggressive, but to keep dogs away from the property if a female is in heat, or have one that's not neutered run off and get somebody's poodle preggers.I'd also require renter's insurance with a rider for the dog, if there is such a thing.Ironically, the only breed that has ever attacked dogs of mine, all different types of terriers of around 20 pounds, have been german shepherds.

Tell the tenant to pound sand.

This chart says a 75 gallon aquarium weighs 850 pounds when it's full:http://freshaquarium.about.com/od/aquariumsandstan...So, I'd argue that the weight alone, could result in extensive and expensive damage to your floors/flooring. 

Something you need to verify.I do have an emotional support animal for my disability, but I also rent where dogs are allowed anyway, and I have a dog under 25 pounds, so any place that accepts pets, will accept my dog.  

I use a standard scoring system.Find out if your insurance coverage disallows any breeds.You may end up needing to accept an undesirable animal, then you have to hope for the best and keep them accountable to the rules, damages, and quiet enjoyment for others.

I don't allow any dog over 25 pounds, so that limits how not only how dangerous they can be, but also limits potential damage.

We allow pets in our condos, in accordance with association regulations - one or two full grown pets under 25 pounds.

There's no visible evidence, aside from the 42 pound bag of cat litter.I did some research and found I can photograph urine stains if I illuminate them with a UV light. 

I rent where animals are allowed, and I got a dog that is under 25 pounds, which are accepted everywhere that allows pets - especially so nobody knows she's a service animal.Because my dog is my service animal, though, I don't have to pay the pet deposit.