Bearded Box Turtle 68

I am most likely getting an African Clawed Frog. I have a 20 gallon long setup and have yet to do anything with it. I was thinking about Fire Bellied Toads the other day but i am not sure about the lifespan of them. I have heard 5 and 30. I would really like an honest response of the lifespan so i know what i am getting myself in to. (Such as how long i'll have my frog). Thank you for any replies.