20g stocking help

[Fishman007]

Def like the Cory's better. Understand how to change substrate. Is it realty necessary to do it if the gravel is pretty smooth. Speciality fish store people said would be fine. If I do change to sand should I wait till fully cycled?

No just take out 50% water and put fish in a bucket with airstone and heater.then get a 5g bucket and rinse the sand really well untill water runs clear, then place the sand in the tank and wait 5 mins, then put the plants and fish and decor back in includeing the water that was in the bucket with the fish (the tank water), then turn your filter back on and put the heater inside. (Make sure filter is not running while doing this process as debris can break or damage the filter.) now the water will be cloudy for 24 hours and you bacteria should be ok but you should check you ammonia and ph often after this.