If you decrease resistance the current will increase or decrease?

It depends on whether the material is ohmic or non-ohmic.

If it is ohmic, then it will obey Ohm's Law, and its resistance will remain constant if the current decreases.

If, on the other hand, it is non-ohmic, it will not obey Ohm's Law and, if the temperature of the conductor falls (assuming it is a metallic conductor) due to the fall in current, then its resistance will fall too.