Biotoecus opercularis
Biotoecus opercularis inhabits Brazilian rivers in the wild. The fish stay in the shallow, sandy substratum covered with a thick layer of fallen leaves and tree branches. The water in these areas has a brownish colour, which is caused by organic matter decomposing on the bottom.
Male Biotoecus opercularis is smaller in size but has a more elongated body and more colourful and elongated fins than females. Males have small green spots on their dorsal plumage. Their caudal plumage has the same spots, only red and blue. the anal fin is red-blue in colour, with yellowish and greenish spots with a silvery sheen. Adult males have thread-like upper and lower tail blades. The maximum size of the fish is 3.5-4 cm.
Biotecus opercularis has no particular requirements for bottom décor. The fish are happy with sandy bottom with snags, arranged so that the aquarium was a lot of shady areas and various caves.
Placing pre-dried oak, beech or almond leaves at the bottom, makes the aquarium conditions as close to natural as possible. Furthermore, bacterial colonies will develop in such a substrate, which serves as good additional food for the fry. Replace leaf litter every 3-4 weeks with new litter.
Rainbow Biotekus desirable to keep in a species tank or community aquarium together with small, peace-loving fish. There should be 3-4 females per 1 male.
Water quality is important in the life of these fish, so do not introduce them into an aquarium, which has not yet established biological equilibrium. Water parameters: temperature 25-30° C, hardness dH 5-15°, acidity pH 4,0-6,5. Requires filtration, aeration and a weekly change of 1/10th of the aquarium water with fresh. The water current in the aquarium should be minimal.
Low light is required. If plants are to be raised in the aquarium, please consider this requirement and select a plant species that can grow in these conditions.
The Biotoecus opercularis feeds on small insects and their larvae in nature. Under aquarium conditions, these fish are fed with frozen and live daphnia, artemia and bloodworms. Feed the fish at least 2 times a day.
Reproduction
Biotoecus opercularis breeds in the aquarium. The female lays eggs in crevices and the inner walls of caves, as well as on the underside of broad leaves of plants. A sign that the female is ready to spawn is the pinkish abdomen colour, while her pelvic fins turn bluish.
The eggs incubate for 3-5 days. The hatching larvae spend the first few days in the same place where the female laid eggs and feed on their yolk sacs. Once all the nutrients in their yolk sacs have been absorbed, the fry gather in flocks and begin to swim and feed under the supervision of the female. The male usually does not take care of the fry.
The fry are fed live dust and artemia nauplii 4 times a day.
