turning off water to toilet

sorry for such a n00b question but I can't figure out how to turn the water off to my toilet. I have attached a picture. I don't know if it can't be turned off (I live in a rental in an apartment building) or whether I need a tool to turn it off.

Thanks so much!

You need a special tool for that

Kind of a stupid valve to have in a residential setting. Those valves are commonly found in commercial washrooms so the public cannot tamper with them. Service techs have the tool to operate them.

i have a tool, $19.95 plus shipping, $1.95 ===21.90 total

omg, I am so sorry but I giggled. Yes it is a dumb stop to have in a residential building. Call the super.

That stop may have been installed in the rental intentionally so that the owner or management can be called for service to deter residents from tampering with the fixtures or trying their own repairs. I did a valve change out in some rentals a few years ago for just that purpose. One of the tenants became frustrated waiting for service on a dripping faucet, turned the stop valve and somehow snapped it (probably used channel locks) and flooded several apartments.
It's easy to see how the intention of making them tamper proof could back fire on the owner in that situation.