fungus gnats. caused from wet soil . do three things . let your soil dry out before any more watering. top two inches should be allowed to dry out between waterings . gey some yellow sticky cards they will help by catching the adults before they can lay more eggs which can only mature and hatch in WET soil . and finally third get some food grade Diatomaceous Earth and use it sparingly as a top dressing to the soil , this stuff destroys the little bastards in the larva stage before they can hatch .. this is how every grower handles fungus gnats .good luck