Nannostomus Beckfordi / Morthenhaleri

[Daniel D]

Hi, looking for straight advice.

This is getting urgent, more fish are starting to show symptoms.

100-liter blackwater. Fish are wild-caught.

Three weeks ago I had a clear rotten-egg smell (too-deep sand + U2 had been off).

I did a heavy clean, reduced sand to 1–2 cm, and large water changes, smell disappeared and has been gone ~20 days.

Now several N. mortenthaleri are rapid mouth-gasping and staying in the dark under roots/pump. They doesn’t eat, One skinny Amaya died.

I ran one round of eSHa gdex in the display (Fluval U2 + dual sponge filter, strong surface agitation). NH₃/NO₂ read zero.

• 
  What’s the next step? Proceed with prazi round #2 anyway, or switch to flubendazole in? How long can gill behavior persist after an H₂S incident, or should I chase another cause (flow/microbubbles)?
  
  Water parameters
  
  • pH: 5.0
  • Nitrates (NO₃⁻): –
  • Hardness (GH): 4 dGH
  • Nitrite (NO₂⁻): 0 mg/L
  • Ammonia (NH₃/NH₄⁺): 0 mg/L
  • KH/Buffer: ≈0 dKH
  • Water Temperature: 26.5 °C

 

[GaryE]

My read is the fish have had severe damage from the water quality issue, and no meds are called for. Either they recover from what seems to be a physical injury, and survive the healing period, or you will lose some beautiful, rare and expensive fish there.

I would go with intense water changing, being very careful to maintain stability. I have brought fish around after shipping, which can cause similar injuries, but it took several weeks of intense attention, with many small water changes weekly for several weeks. Success is never assured.