Diagnosing the issue?
Hi, new to medaka. I ordered a set of 8 Red Emperor Longfin medaka from Dan's Fish, and they arrived just over 2 weeks ago (17 days). During the first week, I had one male pass away, which I chalked up mostly due to shipping stress; it exhibited behaviors of lethargy and was not interested in food. However today I saw another that another just started exhibiting the same behavior. This one is either hiding near the java fern or in this pic at/or around the bottom corners of the tank. It was mostly uninterested in food when I tried using a pipette to entice it. Overall, I don't really see any obvious signs of like sickness (pineconing or ich) but maybe I don't see it? Does anyone know what might be wrong? One thing I could say is it does seem to be consistently opening and closing its mouth so maybe gill issues?
The other 6 are active and are consistently foraging, with the females producing and laying a fresh batch of eggs on the java moss just today.
Tank parameters: 15 gallon, temperature 76-78F, Ammonium: 0.25ppm, Nitrite: 0ppm, Nitrates:0-5ppm. Established 2 years back.
In terms of feed usually a pinch of bug bites/hikari micro bites, either once or twice a day.