I have a pearl gourami which is deformed, with an upturned mouth/nose. He seems to be a healthy, aggressive fish, and was picking on my other male. So I put him in with some South American cichlids. It does fine in there.
This morning when I got up, all of the fish in that tank were at the surface. Clearly low on 02. I turned off the under gravel powerheads and added air stones, which seemed to solve the problem temporarily at least. But I watched the gourami, and it was still returning to the surface to breathe at frequent intervals.
It occurs to me that they can be used as a canary, to monitor the water. They can breathe air, and also have gills, but their gills probably are less effective than other fishes gills. If the gourami surfaces frequently, the water may be low in O2!
This morning when I got up, all of the fish in that tank were at the surface. Clearly low on 02. I turned off the under gravel powerheads and added air stones, which seemed to solve the problem temporarily at least. But I watched the gourami, and it was still returning to the surface to breathe at frequent intervals.
It occurs to me that they can be used as a canary, to monitor the water. They can breathe air, and also have gills, but their gills probably are less effective than other fishes gills. If the gourami surfaces frequently, the water may be low in O2!