Why do apartments make you pay rent for your pets?

Why do apartments make you pay rent for your pets well mine does even little pets like fish

Sounds like daylight robbery to me. Is it even legal!?!

many rentals impose pet deposits...but that is usually for dogs or cats...to cover the cost of potential damage.

They probably have a policy across the board...ALL pets, regardless of size or species. You with fish are getting ripped on it...because they don't cause damage...It isn't against the law at all...

p

To cover damage that can be caused by pets.
Fish tanks can also cause damage if they leak although I have never had to pay a pet deposit for a fish tank.
That is a new one on me.

I had to pay a one time deposit of $50 for my aquarium on the off chance that it broke and they would have to replace a section of carpeting. It didn't- but the idiot across the hall's did, and they didn't tell management, and had a lovely moldy carpet and portion of the wall wall to replace when they moved out.
Dogs and cats are pretty destructive too. YOURS might not be- but other's are; and they can't just take your word for it. Simple things like urinating on the floor and it staining- it's hard to sell a place to somebody that has urine stains all over the place. It's also unsanitary. They have to pay to have the place thoroughly cleaned afterward because their next tenant may have a severe allergy and could sue THEM if they have a reaction to dog hair. That kind of stuff. A lot of it is bogus though.