3x oto deaths, 3 weeks

[alexyay]

I might as well double check here -

I think it's most likely due to the nitrates but the symptoms are a bit off. Something must be spiking in my tank - I know that I lost a threadfin rainbow (body not found) but that was 2-3 weeks ago - all other fish are doing great. The only fish that *could* be dead are the kuhlis as it's hard to count them! But I definitely have 3/5 and don't know why one would have died.

Anyway, whatever is causing my nitrates to spike (moving in exactly one week, tank will be redone and stocking will be reduced for now), they got up to 80ppm. All other fish are fine. But this is most likely what killed the otos. I did a 75% change 2.5 weeks ago, and have been doing the regular 25% weekly since (assumed it /was/ an irregular spike, as I've never had issues with this tank before). The spike is weird, because I've actually been reducing my feeding.

> Important paragraph - However, each time they died, they developed this "bloated" looking stomach within 12 hours of their death. Each time I looked at them and went "woah, you've gotten big!" - the first one I thought was bearing eggs. It died a day after a water change. The second one died two days after that (got big as well). 2 weeks later my final one died - earlier today I noticed it was looking big too (stupidly, it didn't even occur to me that it was the symptom of just-about-to-die) and found it dead tonight. Nitrates are somewhere between 20ppm and 60ppm. Did a 25% change tonight, will do 50% tomorrow.

120L, Aquis 1000

2-3x hara cats

5x kuhli loaches

5x american flagfish

4x threadfin rainbowfish

1x honey gourami

1x thicklipped gourami

1x L129

1x banjo catfish

(used to be 3x otos)

But yeah - has anyone experienced the "bloated" look before death due to nitrates? Or is this possibly something else? If it's a disease I want to make sure as I want to eventually put otos in all my tanks - they're one of my favourite fish

Uh, ignore the algae corner. The corners get algae 'cos there's hardscape and it's hard to get to the back!