I picked up some ornate glass tetras/crystal rainbow tetras (Trochilocharax ornatus) from the Wet Spot a few weeks ago. A couple came in with white cloudy areas in their flesh that I attributed to stress. I started doing 25% daily water changes, but symptoms have only worsened. Now, most fish have the cloudy patches pictured here.
A Japanese blog
mentioned that all of his T. ornatus developed these symptoms and over the course of a couple months, all died. I’ve also seen lots of posts about glass catfish getting cloudy white patches when stressed but I’ve never seen a post where someone describes a recovery.
What's the cause? "Stress" is a catch-all term and is frequently the given explanation when a glass catfish goes white, but it's almost impossible to find examples of glass tetras going white.
So what could be stressing them? Water parameters seem like they'd be ideal for a wide variety of fish. There are no other fish in the tank to stress them, they eat flake food from my hand, and literally never hide. Lighting is very dim (maximum of 20%).
Disease? I'm not seeing any symptoms of the most common fish diseases. All have a healthy appetite.
Perhaps the fish need truly acidic water? I’d prefer not to mess with pH as I’ve read it’s best avoided. I could put some peat into the filter to try softening and acidifying the water, but I wanted to get some opinions. Boston area tap water is annoyingly high (~8.6) due to pH-raising additives to mitigate leaching of old pipes. Once aerated it drops down to around 7.5. RO won't be an option for me until I move in June.
Or maybe they need dramatically cooler or hotter temps than 75º? I can't find any definite info on where they're collected. The only rumor I’ve found is that they were collected near Loreto, Peru.