Care
The Crescent Betta is known from heavily vegetated, sluggish ditches, lowland swamps, rice paddies, and stagnant pools. The substrates vary from leaf litter, mud, sand, and silt, and there is often minimal dissolved oxygen in the water.
The aquarium should be mature and the water soft and acidic (peat filtration suggested). Provide a dark sandy substrate and dense planting with additional hiding places amongst tangles of driftwood. Dried Indian Almond leaves (Catappa terminalia) could be scattered on the substrate for a natural effect - these will also aid in sustaining the required water conditions, but will require periodic replacement. Filtration and water movement should be very gentle, and small partial water changes will help to keep nitrate to a minimum. These fish have the ability to take in warm air from above the water's surface, so a small gap must be left between the surface of the water and the cover slides in order for the fish to accomplish this. The Crescent Betta is not suitable for the general community aquarium and is best maintained in an environment that prioritises their needs - dense areas of planting to enable fishes to avoid one another and tankmates such as Rasboras and Khuli loaches. Groups containing multiple males may be kept if the aquarium is large and there is an abundance of hiding places/visual barriers, but do observe carefully. Even a large aquarium with open sightlines will prove problematic for this type of grouping and in this case it is better to keep a single male with multiple females, their name (im-bellis) might translate as 'peaceful' but this is only in comparison to species such as splendens. Never attempt to house with other Betta species.
Note that many of the fish sold as imbellis may actually be close relatives such as wild-type splendens or mahachaiensis. For this reason, it's best to select potential breeding stock from a single source and enquire about location data if available. True imbellis have turquoise bars on their gill covers.
Feeding
Small frozen foods such as bloodworm, white mosquito larvae, vitamin-enriched brineshrimp, daphnia etc. Will also take flake and "Betta formulas" from the surface of the water.
Breeding
When ready to spawn, the male will build a bubble-nest at the water's surface amongst floating plant cover, and will take on intense colouration as he tries to entice the female underneath it. As the eggs are expelled and fertilised, the male catches any that stray and places them in the safety of the bubble-nest. Once spawning is over, the female takes no part in brood care, and it is the male who tends to the nest. There is normally no need to remove either of the adult fish as they do not usually eat their eggs or fry. The eggs should hatch in 24-48 hours and the fry are usually free-swimming 3-5 days later, at which time they may be offered tiny foods such as infusoria. It is of extreme importance to maintain a warm layer of air between the surface of the water and the coverslides at all times whilst the fry are developing their labyrinth organ, critical during the first few weeks of their life.
