The Mosquito rasbora (sometimes called Chilli rasbora), yet another small member of the Boraras genus, is a shy freshwater fish that grows only up to 1.5 cm in lenght and is native to the swamps of South West Borneo, Indonesia.
This species is endemic to South East Asia, particularly to the Borneo island. Known to be located in the Indonesian province of Kalimantan Selatan, the Mosquito rasbora’s natural habitat consists of rivers, black water streams and swamps.
These bodies of water are usually tinted dark brown due to the tannins released from decaying organic matter like leaves, twigs and tree branches. This process gives the water an acidic property with a pH value as low as 4.0.
The fish thrives in densely vegetated areas and prefers a dimly lit environment, giving its shy behavior. In order for it to feel safe and comfortable in your home aquarium, you should try to replicate these conditions as much as possible.
With its distinctive colors and pattern, the Mosquito rasbora displays an orange-red body color with a brown-black mid lateral stripe and a dark spot at the base of the caudal fin.
Because of its shy nature and very small size, this fish is not suitable for community tanks. You either keep it alone or with other small and peaceful fish like Strawberry rasbora or the Least rasbora.
Mosquito rasbora are a shoaling species and so it should be kept in groups of at least 10 members. Doing so will make them more comfortable in the aquarium environment.
In its natural habitat, the Mosquito rasbora is an avid micropredator, feeding on zooplankton, worms, small insects and crustaceans.
While not a picky eater, make sure to provide the Mosquito rasbora with a varied diet. Beside staple dried foods like flakes and pellets, the fish will reach its optimal form only if you feed it live food such as Tubifex, Artemia and microworms, on a regular basis.
Chopped-up bloodworms are also an option as long as the pieces are small enough for the fish to easily consume.
Feed once or twice a day and make sure the food is eaten in a short period of time, around 3-5 minutes as leftovers will usually reach the bottom and spoil the aquarium water.
Mosquito rasbora males are slimmer and slightly smaller than females. They also display brighter colors: dark red and black highlight on fins. This is especially observed when they’re in breeding form. They will compete with each other for female attention, becoming more aggresive and territorial. The dominant males in the group will also showcase a deeper red.
Females are bulkier and not as intensely colored. When they carry eggs you can easily notice their bellies becoming more round.
Upon reaching sexual maturity, they will lay eggs almost daily. The parents will attempt to eat the eggs if they spot them so it’s best to remove the pair once the spawning process is over.
If your goal is to keep as many fry as possible then the best approach is to separate the breeding fish into a smaller tank (10-20 liters). Add heavy vegetation to the tank. Java moss or any other kind of aquatic moss works best for this purpose.
Keep a small air-powered sponge filter to maintain water quality in the breeding tank. The temperature should be slightly higher than usual, around 27 – 28°C. If you want, you can condition the fish a couple of days prior the spawning, by feeding them quality fresh live foods.
Once the eggs are laid and fertilised, remove the adult fish from the breeding tank. After 24 hours the eggs will hatch and the fry will live off of their yolk sacs. Feed them infusoria and freshly hatched Artemia after another 24 hours.