Cockroaches
The majority of cockroaches can withstand mild radiation, and 20% of them can withstand radiation at the level of an atom bomb (10 000 rad). In fact, cockroaches were discovered to be in excellent health and condition approximately 1000 feet from the location of the Hiroshima atomic bomb drop.
Scorpions
Although no rigorous research has been done on the amount of radiation that scorpions can withstand, it is also believed that they can withstand nuclear attacks better than most other animals.
Fruitflies
The fruitily's tiny body, albeit highly bothersome in the heat, is incredibly helpful to them when exposed to radiation. They can survive up to 64,000 rads.
Braconidae Wasps
Some of the strongest animals on the planet are members of this mostly parasitic wasp tribe. Wasps can withstand 300 times more radiation than humans can, despite the fact that it is enjoyable to dislike them.
The Tardigrade
The Tardigrade can endure extremely harsh pH, water, temperature, and air deprivation circumstances. When they were sent out into vaccum of space, tardigrades have returned in pristine condition.
The Mummichog
They may thrive in the most soiled, chemically contaminated areas of the ocean. Through salt and water, they are very radiation-resistant.