Cockroaches
Most cockroaches can survive moderate amounts of radiation, and 20% of cockroaches can survive high atom-bomb level radiation (10,000 rads).
Scorpions
They can already take a very high level of UV radiation, and some even glow in the dark.
Fruitflies
Tiny, and very annoying in summer, the fruitily’s small body is very beneficial to them during radiation exposure. They can survive up to 64,000 rads.
Braconidae Wasps
Wasps are fun to hate, but they can sustain 300 times more radiation than humans can.
The Tardigrade
Extremophiles are creatures that can survive in really really extreme conditions of pH, water, temperature, and lack of air.
The Mummichog
They can live in the dirtiest, most chemically polluted parts of the ocean and be perfectly fine.
Deinococcus Radidurans
This little bacteria is in the Guinness Book of World Records as the most radiation-resistant living creature to exist.