Wow really? Because I had heard that they are also notoriously difficult to breed, and will only do so when they are in good water conditions, and mine seem to never stop breeding. I was sure that was a sign they are happy with the environment, though they have stopped since the fungus first...
I have a 55 Gallon Brackish with 6 young Celebes Halfbeaks, 3 young Scats, a green spotted puffer and a Knight goby. They used to be in two tanks, but a couple of months ago, one sprung a leak and I had to combine them. I guess because they were suddenly all together it stressed the halfbeaks...