Tiny black bugs eating my plants
I was hoping someone could help me out here. I have some sort of very tiny black (possibly black and white striped) bugs eating my bacopa carolinia. I noticed them in the substrate of the tank a few months ago, but a few weeks ago, I noticed them INSIDE the top section of the stem on one of the plants. The stem section they were in had become transparent, so I figured they were eating dead plant material. However, yesterday I noticed that they had moved down to the next stem section (the "sections" are separated by leaves) and had begun eating that section from the inside. Before this, that section had been healthy.
I have not seen them in any other plants, but I have noticed my ludwigia repens is developing dark brown/black stem sections that rot away and separate from the rest of the plant. It's possible this is caused by something else, but I am wondering if they have gotten into those too.
Any idea what these are and how I can get rid of them?