I was thinking of adding blackworms to my aquaruim soil, thinking it would be beneficial for breaking down detritus and be good food for my kuhli loaches. I just want to make sure they won't hurt my tank. I appreciate any feedback. Thank you.
I had blackworms in my tank at one point, and liked having them. They didn't cause any problems for me. (I had to move and couldn't take the tank, so I don't have them now.)
Some people don't like to see little worm tails sticking out of the substrate and wiggling around. Personally, I liked watching them. If your kuli loaches hunt them, the worms may stay underneath out of sight. That happened in my tank after I added fish.
Some people don't like seeing the dirt piled up like little ant hills. Or maybe it's worm poop--I couldn't easily tell the difference, but it certainly looked different than the gravel that was on the surface before I added the worms. It didn't bother me, but I don't know about you.