Need some advice on the best way to get rid of detritus worm infestation.
Two weeks ago my last couple of zebra danios died abruptly in my 10g tank, which was heavily planted with java moss and other assorted aquatic plants, and has been established and running for nearly 2 years. Did an API water check and pH was actually at 6, ammonia at 0.25, and nitrates/nitrates was 0. The pH of my local tap water (after dechlorination) is 7.2.
Seeing as there weren't any fish left, I turned off the filter pump... 24hrs later I noticed hundreds of tiny "roots" poking out of the substrate, waving gently even though there was no current. Did a bit of looking up and turns out they were detritus worms, to the scale similar to a video on youtube if you search "tons of detritus worms" (I can't post links yet). I left the tank as it was for a few days (without aeration) as I was busy with work, and everyday more and more worms emerged, scrambling and climbing onto the java moss and other plants. I'm not afraid of worms but even I found it very disgusting.
Over the past week I did what I could to get rid of most of the worms (and buried fish poo) through very vigorous siphoning of the gravel substrate during daily water changes. I have also quarantined the plants of the tank for 12hrs in a separate tub to shake out the worms that were hiding in the roots and driftwood crevices. I have also cleaned the filter and found some worms frolicking around. I then replanted some of the plants (cutting down heavily on the java moss) back into the tank. I left the tank to run for a day, and a quick API check several hours later revealed that the pH was now at 7.2 and ammonia was 0.
Thinking everything must be alright, I went to the LFS and bought 6 ember tetras + 2 corys yesterday. The fish settled in well, and I sprinkled a tiny pinch of crushed pellets, which were promptly eaten. but this morning I came to discover the tetras & the corys were all making trips to the surface to breathe every 2 mins.... and the worms are back in substantial numbers, poking out of the substrate! The corys had 0% interest in the worms.
I did a quick check and pH has dropped to 6.2 (from 7.2) overnight, and ammonia has gone up to 0.25. Thinking the drop of pH and the breathing pattern was probably lack of oxygen/ too much CO2, I did a 25% water change, and sucked up at least another 20 worms from the gravel.
The fishes seem to be doing fine at the moment, but I am pretty stressed about the worms that are still lurking, affecting the bioload and CO2. Also the daily thorough siphoning isn't really aligning with my intention to grow java moss and other plants.
What should I do? Should I:
1) keep up the daily 25% water change for damage control, and hopefully reduce the worm population as gently as possible?
2) evacuate fish, quarantine plants, blast the tank (and filter) with some copper-based treatment to get rid of the worms?
3) Same as 2, but discard substrate entirely?
Thanks for reading my incredibly long first post and I hope to hear from the experts soon.
- Java Moss