Anabatoids: A Primer
Anabatoids are a group of fishes in the Anabantoidei family that can assimilate atmospheric air, which is an adaptation to survive in Oxygen-poor waters. In fact, Anabatoids are one of the few fishes that can drown if unable to get to the surface to breathe.
Air goes into a tightly wound, maze-like, cartilaginous organ just above the gills known as the labyrinth organ. Air captured in the organ is spread through the fish by the bloodstream. Only mature fish have this organ; very young fish breath solely though their gills, developing the labyrinth roughly six weeks after hatching.
There are several sub-families in Anabantoidei; Anabantidae, Belontiidae, Osphronemidae, Helostomatidae and Luciocephalidae. In this primer of Anabatoids, we will cover species from all those families.
Spawning tanks should be prepared if one wishes to breed the Anabatoids.
All Anabatoids are old world fishes, with the majority of species from South-East Asia. There are a few in Africa. All these fish need stable, mature aquariums, and planted tanks are advised for most of them.
Now, the species.
Ubiquitous when the word Betta is used is Betta splendens, a native of Thailand.
In nature, B. splendens lives in small, plant-choked ponds, rice paddies, peaty swamps and even in stagnant, polluted ditches. In other words, acidic, low Oxygen environments. Thus, these fish have a highly developed Labyrinth organ, which is why they survive so well in the tiny containers in fish stores.
B. splendens males are well known to fight each other if kept together in an average-sized aquarium. In nature, where the wild Betta looks nothing like the flowing fins and dazzling colors of the domestic strains, males each stake out a territory, usually under a floating plant. He defends that territory as he tries to attract females, and in the natural climes, each male can have a territory, so there's little to no conflict among males. A Betta tank should be well covered for best results, since they breath better in warm, humid air.
To this day, there are still male Bettas bred for fighting among some classes of Asian society. They have been selectively bred for more than three hundred years for large heads and just a bit more than normal finnage. A fight is so quick the fish are a blur, and the loser, with fins shredded, retreats and is unwilling to fight further. Much money changes hands betting on the outcomes of these fights.
The wild Betta splendens is quite attractive in his own way. His body is very dark green, blending toward red near the anal fin, which is red rimmed with black, as are the ventral fins. The dorsal is blue, striped with waves of green, and the caudal fins has bright blue rays with red ground. His fins are a good deal larger and he's far more colorful than the female, which is about a half-inch smaller than his 2.25 inch length. She's a muddy brown unless she's ready to mate; then she dons a yellow cast with black bars. Female Bettas are much more difficult to find, since the males are very much the show.
Betta splendens is a bubble nest builder, that is, he blows bubbles coated with his saliva into a roughly oval mass. He usually anchors it under or beside a floating plant if he has one, somewhere in the tank if he doesn't. Those nests rarely succeed, so floating plants are a key to home breeding of Bettas. A gravid female approaches, head down, slowly edging toward the male, and if he accepts her, he wraps his body around his mate, sometimes repeatedly, and the eggs (between 10 and 200) are expelled and fertilized as they very slowly fall. When finished, the male chases the female off and he gathers up each egg and spits it into his floating nest. She must have a place, like a clump of plants, to retreat to, and then removed promptly, or he'll kill her. He knows she'll eat her eggs and fry if she gets a chance.
At 82 degrees the eggs hatch within 72 hours, and the fry hang by their heads among the bubbles. Any that fall are quickly spat back into the nest by the male. Within a week they are free swimming, and must have the tiniest of foods (infusoria, followed by rotifers) for at least ten days, before they can take live baby brine shrimp and microworms. Males must be isolated as soon as they grow a bit, since they will start fighting at a young age. Females can be kept together without problems. Lowering the water level in the fry tank to six inches serves to get the fry and food together, and also is low enough they can start developing their labyrinth organs.
Domestic Bettas, though their kind developed in very soft and acidic waters, are quite adaptable as to pH and hardness from decades of commercial production, and can be kept between pH 5.0 to 8.0. Wild caught examples, however, must have waters very similar to that they came from. Bettas much prefer floating foods, and it is quite helpful if they get the easily cultured wingless fruit flies occasionally. Stay away from flake foods, since they can easily compact in their intestinal tract, resulting in many unexplained deaths. Pelleted foods that float are a better option. Betta splendens live a maximum of three years, with two years more common. Temperatures should be in the low 80's for general maintenance, and water still, since splendens does not do well in aquariums with powerful filtration.
Bettas thrive in well planted tanks, since they frequent stands of aquatic plants, if they have them, in nature. A single male can be kept with several females, as long as the tank has many areas where they can get out of sight of him. It's best to have at least five females, so he cannot target one of them with aggression. Floating plants over the main swimming area will make your Bettas more secure and thus active. Tankmates have to be small, like neon or cardinal tetras, and other than cherry barbs, barbs should be avoided as they pick at the flowing fins of the male. Corydoras catfish are good tankmates, but Doradids and things like Pictus cats are ill advised, since they'll eat sleeping tetras, and even the smaller female Bettas.
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