Kribensis breedin/fry question?

A young pair and a small aquarium, 40 - 50 liters, could have a small batch of fry, or there could be more fry with the father that you didn't see yet. I've bred kribs since 1970 and I have learned don't let them see you looking at their eggs or fry. Stand on the other side of the room and use your camera zoomed in to watch them. Until the fry get big enough to look like miniatures of the parents, keep your eyes off the fry and eggs when near the tank.

Some possible reasons for a small number of fry....

The male was inexperienced or had very few mature sperm, and only fertilized a few of the eggs.

The parents thought you saw the eggs, and relocated them several times whenever they thought you were looking at them. They would dig deeper, steeper pits for the eggs each time they tried to find a better hiding place, that could have collapsed over most of the eggs or fry.

There was not enough microfauna in the tank on fine leaved live plants like Java moss, and not enough microworms and newly hatched baby brine shrimp for all but the few biggest fry to survive.

They definitely laid more eggs than that, but there are a number of things that could have happened. Some of the eggs may have been infertile. They could have been spooked at some point and eaten some of the fry, or possibly some may have been drawn into the filter. I assume you thought of protecting them from that though. The other possibility is some other fish may have eaten some. Even an apparently docile catfish could be guilty of this.

As the parents grow larger, they will lay a larger quantity of eggs. If you think they may have eaten some of the fry, place their spawning site as far back in the tank as you can and surround with dense vegetation. It will be harder to observe them, but they should be less disturbed by activity outside of the aquarium.