For a breeding pair, a 20 gallon tall should be used. But for full size adult breeding pairs, a 29 gallon is best. Keep in mind, this is ONLY for a confirmed breeding pair. Don't put a male and female together and expect them to breed.
I keep my tanks at 82°F (28°C), especially in my community tank with discus, angels, clown loaches, various types of cories, various plecos, and rasboras.