Unexplained BN death

Yesterday was big clean day, changed about 30% of water and vacuumed under all the driftwood. Everyone was happy.
This morning, my BN was floating and rather deceased. His tummy looked a little lumpy, perhaps a little bit bloated, and there was a very strange orange oily substance secreting from somewhere. Not sure where; I wanted him fished out before too long. It formed little drops in the water around him.

Does this sound familiar at all? Sorry the details are vague, but he honestly hasn't shown signs of being ill at all. Always an active and social fish. He was still only young, maybe 7ish cm. One thing was water test today showed 0,0,20 but pH at a never seen before low of 6.0.

Any suggestions?



One other thing, unrelated, the bristles on the nose ...if they don't have them, does that usually indicate male or female?
Thanks, lovies.

hmm, ph 6 wont kill him, not ideal obviously but would not cause sudden death.
how often do you do big cleans days? maybe the disturbance of the substrate released long accumulated toxins (should stir substrate every few weeks IMHO)? is it gravel or sand and how deep is it??
what other fish are in the tank and are they ok?

oh, lack of bristles up the nose is female.

The oily is just the body decomposing. Its good you caught it quickly so it didn't pollute the rest of the tank.

I would say you disturbed some nasty bacteria under the gravel or some long dead and buried food which it ate and got bloat, or you did too much of a clean up and got a mini cycle happening.

I usually drop in a dose of Prime liquid or similar if I am doing a big clean like that so it carries the water for at least 24hours safe to plecos while the bio catches back up.
It doesn't usually take long.