Corys Which Species Is Easiest To Breed?

Ammonia of 1 is too high, you need to do a large water change to get it below 0.25.
Nitrite of 2 is too high, you need to do a water change to get that below 0.25 as well. In fact, you need to change all the water. Leave just enough to allow the kribs to swim upright, refill then test again. If either are over 0.25, do another water change. With water changes this big you need to get the temperature of the new water to the same as the tank water. If you have a combi boiler, mix hot and cold tap water. if you don't have a combi boiler, you need to mix in some boiling water from a kettle.



The tank is only big enough for small cories; the easiest ones to find in shops are pygmy cories which will breed in tanks. Once the tank has finished cycling.

Best of luck with getting your cycle under control. Be patient, keep testing the water and performing water changes to keep the toxins low, and I'm sure it will sort itself out eventually. 

The pandas are nice looking fish. 
I have peppered cory in my temperate tanks, as they are good at lower temperatures, and they are very entertaining feeders, the way they rummage through the sand. As I said in another thread, I was over the moon when I witnessed one fart.