I'll echo Squishy's comment regarding that they might "survive" but the conditions of the water during a cycle are deplorable and unhealthy. Imagine living in your bedroom, that you can't leave, and is filled with dozens dirty diapers and dead rats that are rotting. When you go to the bathroom, it adds to the stink and the mess.
This is what you're putting animals through when you use them to cycle your tank.
Please read our article (instructions) on how to Cycle Without Fish
, it's faster and easier than using fish because you don't have to worry about water changes or the levels getting TOO high, because there's nothing alive in the tank so you can let it spike all it wants and create a boat load of bacteria in your DSB