Anytime a tenant has complained about it being too dry in the house, I tell them to get a small aquarium.

Like "No water beds or aquariums."

If you've ever walked into a house where they abandoned it leaving the aquarium full of fish, you'll never allow those again.

Before making any decisions, sit down and have a talk with your agent about prices in the different areas, and do your due diligence regarding safety in each area.The great part about investing in Baltimore is that it has Johns Hopkins, the convention center, the aquarium....

One of the few things I would consider are things that live in an aquarium.

Also no exotic pets, no loud birds, and I place a restriction on aquarium size.

Many of my guests came here to do things in that part of town, ie World of Coke, the Aquarium, CNN Center, and I'm sure would have enjoyed being that much closer.  

If your STR has 10 fish tanks inside then you probably have a hefty aquarium bill, if you have a cabin in the mountains, then you should probably account for snow removal, deck staining, and roof repair every few years, etc. 

I arranged to meet them at the house to see if there were any electrical issues, window gaps etc but instead I found x6 LARGE aquariums full of salt water fish. 

(aquariums, waterbeds, water coolers, water fountains, etc.).