Naked Microrasbora
Boraras brigittae
Description
The Naked Microrasbora is a very small, translucent species of fish known for its unique lack of pigmentation, giving it a “naked” appearance. Unlike many other species of Microrasbora, this fish does not have the vivid colors or patterns often associated with the genus. Instead, it has a translucent or pale body, often appearing almost invisible in the aquarium unless the light hits it just right. The body is slender, with a streamlined, elongated shape that allows it to swim quickly through the water. Despite the absence of bright colors, the fish’s delicate appearance, combined with its active behavior, makes it a unique and interesting addition to aquariums.
Habitat Origin
Native to Southeast Asia, specifically found in freshwater habitats of Thailand and Malaysia. These fish are typically found in slow-moving, clear waters with dense vegetation. Their natural habitats are often characterized by soft, slightly acidic to neutral water, and they prefer moderately warm temperatures with plenty of cover. They are commonly found in small streams or forested regions, where they seek shelter and forage in aquatic plants and organic debris.
Aquarium
Ideal Number in Aquarium: At least 6 individuals, as they are schooling fish and feel more secure in groups.
Favorite Food
Naked Microrasboras are omnivores and will eat a variety of foods. They can be fed high-quality flake food, micro pellets, and live or frozen foods such as brine shrimp, daphnia, and microworms. They will also graze on algae and small plant matter, so incorporating vegetable-based foods like spirulina or blanched zucchini is beneficial. Due to their small size, foods should be appropriately sized for their mouths.
Behavior:
Naked Microrasboras are peaceful, active, and social fish. They are generally non-aggressive but can be shy and are best kept in groups to encourage their natural schooling behavior. When in a school, they display synchronized swimming movements, darting around the aquarium together. Although they are shy and sometimes hard to spot due to their translucent appearance, they can become quite active and playful, especially when housed in a tank with other peaceful species.
Special Care:
While Naked Microrasboras are hardy and easy to care for, they prefer stable water conditions. Regular water changes, good filtration, and a well-maintained tank are necessary for their health. They thrive in a tank with plenty of plants, rocks, and other decorations that offer hiding spots. A soft, fine substrate is ideal for them as they are often found foraging along the bottom for food. Strong currents should be avoided, as they prefer calm waters.
Compatibility with Other Fish:
Yes, Naked Microrasboras are compatible with many other small, peaceful species. They can be housed with other nano fish like tetras, rasboras, and peaceful shrimp. They should not be kept with large or aggressive fish that may intimidate or harm them. A peaceful community tank is ideal, with other fish that have similar care requirements.
Breeding Tank Setup
A separate breeding tank is strongly recommended for Naked Microrasboras due to their small size and sensitivity to stress from larger or aggressive tankmates. A 20–30 liter (5–8 gallon) tank is sufficient, providing space for natural spawning behavior and ease of monitoring. The ideal water parameters are pH 6.0–7.5, temperature 24–28°C, and hardness of 4–12 dGH. A gentle sponge filter is preferred to keep the water clean without creating strong currents. Use fine gravel or sand as substrate, and add live plants such as Java moss, Anubias, or small-leaved varieties. Floating plants also help by creating shade and mimicking the fish’s natural environment.
Conditioning for Breeding
To prepare the fish for breeding, provide a high-protein, varied diet. This should include live or frozen foods such as brine shrimp, daphnia, and micro-worms, along with quality flake or pellet food for balance. Conditioning should be done for about a week. Just before breeding, perform a 20–30% water change and raise the temperature slightly to 28°C, which helps simulate environmental triggers that encourage spawning.
Spawning Process
Spawning usually occurs in the early morning or late evening when the water is clean and stable. Males display enhanced coloration and become more active, chasing females to encourage egg laying. Females typically lay 30–100 eggs per spawning event, scattering them among plants or other surfaces. Since Naked Microrasboras do not care for their eggs and may eat them, it’s critical to remove the adult fish immediately after spawning to protect the eggs until they hatch.
Fry Hatching & Feeding
Eggs typically hatch in 2–3 days, depending on temperature. After hatching, the fry will absorb their yolk sacs over the next couple of days. Once they become free-swimming, begin feeding them infusoria or liquid fry food. After about 5–7 days, introduce newly hatched brine shrimp or finely crushed flakes to support growth. Maintain excellent water quality with 10–15% water changes every 2–3 days, using a sponge filter to avoid harming the fry and keeping temperature stable between 24–28°C.
Maturity & Stress Prevention
Naked Microrasboras reach sexual maturity at 3–6 months, and only healthy, well-conditioned individuals should be used for breeding. Males tend to be smaller and more vividly colored, particularly on their fins, while females are slightly larger with a rounder belly when carrying eggs. To prevent stress, avoid overcrowding, keep water parameters stable, and eliminate sudden changes in temperature or pH. Never house them with aggressive species during breeding, as even small disturbances can disrupt the process.