I have a pair of Kribensis raised from small juveniles in my 20g community tank. Lucky me, the two formed a pair! For a few months now, the pair would go through spawning rituals. The female's belly would swell up and turn bright red, the male would chase her around a bit, she'd do that shaking dance thing, etc. Then, they'd retreat to a little castle thing for a day or two, move a bunch of the gravel out, and guard the place fiercely. I never looked for eggs or anything and to my knowledge, either no eggs were ever laid or the eggs were eaten.
Recently, I changed the tank around a bit and added new gravel. The pair went through their usual ritual, and the female retreated to the castle They moved a bunch of gravel out as usual. This time, however, the female stayed in the castle for several days. Later, the male moved into the large resin log decoration and started very aggressively protecting it from any intruders. I watched the female move back and forth from the small castle to the log. Now, both spend almost all of their time in the log and fiercely defend it together. They rarely even leave the log for feedings. I'm thinking this time they might've been more successful in their spawning, but looking in the end of the log I'm not seeing any fry. It's rather dark so I could just be missing them.
How long does it take Kribensis eggs to hatch? How long after hatching are the fry free-swimming? Is there any way to check for fry or eggs without disturbing them?