How long will my fish live without a water pump?

I have 2 plecos and a tetra (buenos aires? I know NOTHING about fish, the tenants before me left them here and I feel bad for them so I try to keep them alive) in what I believe is a 20 gallon tank. The water pump died about 2 days ago; the fish are still kickin', the tetra comes up for air a lot (not jumping, just little gulps) but the water looks pretty clear so I guess the plecos are "vacuuming" quite nicely. I try to circulate the water and make bubbles for them but I don't have time to do that all day. What's the approximate life expectancy for them if I can't make it to the store to get a pump for them tomorrow?