Everyone tries their hand at keeping Betta splendens (Siamese fighter) at some time in their aquatic career. Although they are often kept in community aquaria, this is not the right place for them, particularly not for the males. The trailing finnage is a great temptation to other fishes who will often harass the slower-moving fighter and nip or tear his fins. This puts him under stress; often he will refuse to feed and may even develop bacterial or fungal infections on the damaged fins. In the worst eventuality he may hide away and eventually die. Females, on the other hand, seem to be able to fend for themselves in the average community aquarium of non-aggressive fishes.
In retail outlets male fighters are displayed individually, usually in small compartments within a larger tank. Although at first glance this system may seem cruel, it is designed specifically for their safety and well-being, allowing the fishes to display to each other while preventing them from causing actual bodily harm to either party. If kept together they will actually fight to the death. The water in the system is warm and clean, the fishes are properly fed and, even though they have no aeration system, being air breathers they are able to cope with the situation.
For anyone who is serious about keeping and breeding fighters, special tanks should be used. These are divided into compartments using sheets of perforated mesh or glass dividers which leave a slight gap at the top and bottom, large enough to allow a flow of water through the whole aquarium yet small enough for the fishes not to be able to get into the next compartment. Using such a set-up, it is possible to provide well filtered water to maintain the creatures in the optimum conditions.
When breeding Betta splendens, set up a special tank, which need not be too deep but should contain thickets of plants to give the female cover and also to provide anchorage for the bubblenest. Make sure that the female is well fed and full of roe before attempting to put her with the male. Initially it is best to isolate the female in ajar floating in the breeding tank. The male will start to construct the bubblenest and from time to time display to the female, spreading his fins and shaking. After a hour or so the nest will be quite large and the female will be excited enough to try to follow the male under it. This is the time to try to introduce her to him. If all goes well, the pair will go back to the nest where the-male will wrap himself around the female, so that his vent is in close proximity to hers and then, as the fishes roll slowly in the water, the eggs and sperm will be released. The eggs are heavier than water and will sink towards the bottom. The male will now break off the embrace and catch the falling eggs in his mouth, gently blowing them into the nest; once the female recovers she will join in this task.
The spawning takes several hours to complete, during which time up to 250 eggs will be laid. Once the pair have finished spawning remove the female as quickly as possible, taking care not to disturb the nest. If she is left in the tank, the male may kill her while protecting the nest. For the next couple of days he will dedicate his life to looking after the eggs. Since they are heavier than water every so often one or more will fall out of the nest. The male will carefully catch these in his mouth and push them back into the nest.
On the third day the eggs will hatch but the fry will not become free swimming until late on the fifth or even sixth day after spawning. The fry are quite small and require newly hatched brine shrimp as their first food. Once they are free swimming, the male must be removed before he eats his offspring.
Recently several other species of Betta have been available to the hobbyist. Not all are suited to the community aquarium, and not all build the well-known bubblenest when breeding, but instead fnouthbrood the eggs: so ensure you do your homework before you purchase them.
One of those more likely to be encountered is Betta pugnax, a mouthbrooder. A pair will live quite happily in a soft water community aquarium provided the other occupants are peaceable. Although relatively drab, they have an interesting method of reproduction. The female produces a batch of 10 to 20 eggs which are held in a “cup” formed by the male’s anal fin. She then picks up these eggs in her mouth and spits them into the male’s. The sequence is repeated until the clutch of up to 100 eggs is complete, and they are then brooded by the male. The fry are easily raised on infusoria and brine shrimp nauplii.