Fungus gnats in potting mix
Small dark flies around pots often favor damp mix.

What to look for
Fungus gnats are slender dark flies commonly seen near moist potting soil. Adults are mainly a nuisance; persistent dampness and, in heavy infestations, larvae can also affect vulnerable roots.
What to do
Let the mix dry to the level the plant tolerates before watering again and empty standing water from the saucer. Yellow sticky cards monitor adults; check the mix and continue for several weeks.