Parosphromenus opallios

Parosphromenus opallios is a stunning species of gourami native exclusively to the Kalimantan region of Indonesia. This small freshwater fish reaches a maximum standard length of only 2.5 cm, making it a perfect choice for nano aquariums. The species is distinguished by its vibrant coloration and the iridescent quality reminiscent of opal gemstones, which inspired its specific epithet. Parosphromenus opallios is not just visually appealing; it is also a facultative air-breather, allowing it to thrive in oxygen-poor waters where other fish might struggle.

In its natural habitat, Parosphromenus opallios is usually found in slow-moving streams and blackwater areas, characterized by soft, acidic waters enriched with decomposing leaf litter and organic materials. This environment contributes to the species’ unique adaptations, including its ability to utilize atmospheric oxygen. The fish exhibits a peaceful demeanor, often seen in small groups or pairs, making them an excellent choice for community tanks with compatible species.

Behaviorally, Parosphromenus opallios is known for its shy nature, often hiding among plants and debris. Its coloration can vary depending on environmental factors, with males typically displaying more vibrant hues than females, especially during breeding. Breeding behavior is fascinating; males will display to attract females, and once paired, they engage in a courtship dance that can be mesmerizing to observe.

Due to its limited distribution and specific habitat requirements, Parosphromenus opallios is considered uncommon in the aquarium trade. However, its beauty and unique characteristics make it a sought-after species for enthusiasts and collectors alike.

To successfully care for Parosphromenus opallios, it is essential to replicate their natural habitat. Optimal water conditions include a temperature range of 24-28°C, a pH of 5.5-7.5, and low to moderate hardness. A well-planted aquarium with plenty of hiding spots will help reduce stress and encourage natural behaviors. It is advisable to maintain a minimum tank size of 20 liters to accommodate their needs and ensure stable water conditions.

Feeding should consist of high-quality small pellets, finely crushed flakes, and live or frozen foods such as brine shrimp and daphnia to promote health and color vibrancy. These fish can be timid, so it's important to introduce them to the aquarium slowly and keep them with peaceful tank mates to prevent stress. Ideal companions include other small gouramis, tetras, and rasboras.

Acclimation should be done carefully, introducing Parosphromenus opallios to the new environment gradually to minimize shock. Quarantine new arrivals for at least two weeks to monitor for diseases before adding them to the main tank. Regular water changes and monitoring water parameters will help maintain a healthy environment for these delicate fish.

Parosphromenus opallios is suitable for shipping, provided that proper packing methods are employed to minimize stress. It is recommended to ship them in insulated bags with adequate oxygen supply and to avoid overcrowding, ideally limiting the density to 6-8 fish per liter. Shipping temperatures should be maintained between 24-28°C to ensure their well-being during transit. Currently, Parosphromenus opallios is not listed under CITES, but it is advisable to check local regulations.