Less than two weeks after the bred, the Macropodus look like the want to breed again. The male has built a nest, and the female is hanging around it in a fairly interested fashion. If they do breed again, I don't have anywhere to move them - I just don't have another tank. Sadly, the eggs will probably end up as fish food. I'm more worried about how the male will react - he's likely to go crazy trying to defend his nest, and may actually hurt some of the other fish (he is, after all, easily the largest and most aggressive fish in the tank).
Well...we'll see what happens.
Update: Turns out that events had overtaken me - he already has a nest full of eggs. They must have mated last night. Surprisingly, he seems to have done a pretty good job of defending the nest - it hasn't turned into a free-for-all feeding place.