I can't offer advice on the worms, other than be careful when fish are introduced. I would want to pin these down exactly before introducing fish.
But that fungus from the wood is another concern, perhaps even more serious. Some of this sort of fungus seems harmless, but some is definitely toxic to fish. I have nearly lost fish to this, and know of others locally who did. It is impossible to say what the fungus is without examination by a microbiologist, and there are so many different species. Some is harmless, but not all. Here again, be careful introducing fish. If this were my tank, and with my past experience, I would remove that bit of wood and do a complete water change. Grapewood is particularly prone to toxic fungus, and perhaps Mopani. The lighter coloured woods. With the branch I had, I scrubbed it in hot water, dried it in air, then placed it in a fishless tank for 3 months. Seeing nothing, I assumed it was OK, but I was wrong; within a few weeks of being added to a tank with fish, the fish became lethargic and I found the fungus on the back side of the wood. It is now in the garden where it will remain.
Byron.
But that fungus from the wood is another concern, perhaps even more serious. Some of this sort of fungus seems harmless, but some is definitely toxic to fish. I have nearly lost fish to this, and know of others locally who did. It is impossible to say what the fungus is without examination by a microbiologist, and there are so many different species. Some is harmless, but not all. Here again, be careful introducing fish. If this were my tank, and with my past experience, I would remove that bit of wood and do a complete water change. Grapewood is particularly prone to toxic fungus, and perhaps Mopani. The lighter coloured woods. With the branch I had, I scrubbed it in hot water, dried it in air, then placed it in a fishless tank for 3 months. Seeing nothing, I assumed it was OK, but I was wrong; within a few weeks of being added to a tank with fish, the fish became lethargic and I found the fungus on the back side of the wood. It is now in the garden where it will remain.
Byron.
