The Family Medical Leave Act (FMLA) permits qualifying employees of certain employers with up to 12 weeks of unpaid time off to treat a serious medical condition or to care for an immediate family member with a serious medical condition.
One of the differences about having a pet in a classroom vs. at home is that a classroom is noisier and the pet must become used to many people. This can be stressful on some animals, and we want to keep stress on our pet to a minimum.
I had a small aquarium in my classroom last year and worried about the same thing. I ended up using the 2 week feeder tablet. It worked fine. Come to find out cold blooded fish slow down a lot and eat much less when the heat is turned off. My bigger concern was the classroom temp. I only had a couple gold fish, apparently they're not to picky.