its a cactus [by name, if not botany] ... how thoroughly are you watering it ... mine are kept so dry.. the tops nearly make them fall over ...

google: fungus gnats .. to see if we can ID them ...

the prime problem with gnats .. is too wet media ... which should never be a problem.. on something called a cactus .. eh???

we have to ID them ... to get you on track ... and pix just dont work in this type of case ...

one should not segregate.. its not politically correct.. think hospital.. we isolate ... lol ... the isolation ward ...

ken

I checked the plant this morning, and I'm certain they are fruit flies or fungus gnats as I saw some bigger ones with wings.

The plant lives in my bathroom above a heater and its usually very warm, as a result the plant soil gets super dry and dusty and usually gets water every few days. Should I stop watering them for a bit?

This post was edited by AndrewDS on Tue, Mar 25, 14 at 16:20

Fruit flies don't bother plants. And fungus gnat larvae are clear or nearly so.

See this:
http://www.ext.colostate.edu/pubs/insect/05584.html

Here is a link that might be useful: fungus gnats & more

Could you add a pic of the plant? Is there a lot of dead debris on top of the soil?