AN EXPERIMENT IN MALE-LESS EGG AND FRY RAISING Testing methods of hatching betta eggs without a male to nurse them.
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When my first
spawn failed because the male ate the eggs and fry, I began wondering
if there was a technique to hatch the eggs and raise the fry without
a father. I came up with four.
Technique 1 used a sheet of black, 1/16 inch thick craft foam with a bead of aquarium sealant around the edge. This was filled with a very shallow layer of water and seeded with 50 eggs. The water was so thin that it only covered 3/4 of the eggs. The idea was that if the eggs were in a bubble nest because they needed contact with air, such a shallow thickness of water would keep them moist while exposing them to air. The foam floated on the water in which the spawn took place. The tank was tightly covered to maintain 100 percent humidity so that evaporation and temperature wasn't an issue.
This technique failed because I found it impossible to maintain an even layer of water. It would invariably drain to one corner and somehow leak out, leaving the eggs high and dry.
Technique 2 was the same as technique 1 except I used a small, shallow, flat-bottomed glass bowl. Although the black plastic sheet made observing the eggs easier, I was concerned that chemicals in the sheet might hurt the eggs. Technique 2 was a test to see it that was the case.
This technique failed because while the eggs appeared to grow and ripen, many of them seemed to dissolve. I suspect mold attacked them and in the shallow water, all the eggs were effected.
Technique 3 consisted of a small glass bowl in which bubble nests harvested from the jars of other males had been added. Fifty eggs were dropped into this artificial nest and the bowl covered. Like techniques 1 and 2, this bowl floated in the spawning tank.
This technique failed because the nest disintegrated faster than I could add freshly harvested bubbles to it.
Technique 4 was by far the simplest and, wouldn't you know it, the most successful. I simply floated another small glass bowl in the spawning tank, added 1/2 inch of water and seeded it with fifty eggs. Although several of them dissolved in a way similar to the eggs in the shallow-water techniques, most ripened at almost the same rate as the eggs left with the father. Maturity seemed to come slower because by the time that the father-nurtured eggs were completely hatched, only ten percent of the eggs in technique 4 had hatched. I assume that the reason for this is that in spite of being in the pawning tank, the water in the bowl was slightly cooler than in the bubble nest. The success of this technique suggests that the eggs do not have to be in contact with air to mature. From this I deduce that maintaining the eggs and fry in a bubble nest is a technique developed by the fish to hide them from predation.
As several sources mention, it seems that one of the important things the male does in caring for the eggs is keep them clean of mold that attacks them. The betta in this spawn followed a regular schedule of moving all of the eggs from one side of the bubble nest to the other twice a day. So much handling would certainly allow for extensive cleaning. It might be possible to provide this function by stirring the eggs and following that with a water change twice a day. This is something I plan to try during the third spawn.
Technique 4(a) I harvested 10 newly-hatched fry and placed them in a floating bowl with 1/2 of water. I want to test to see if the fry, once hatched, really need a male to help them mature.
They didn't!
Final results: I couldn't find a good reliable technique that worked. A male is needed to perform the cleaning and disposal jobs necessary to protect the developing eggs.
