Spotted Blue Eye Rainbow
Spotted Blue Eye Rainbow (Pseudomugil gertrudae) is one of the most captivating nano fish available for the planted aquarium. Males display spectacular, butterfly-like spotted fin extensions in yellow and orange, with iridescent blue eyes and a delicate, almost translucent body. They fan their fins in constant courtship displays that are among the most beautiful behaviors in nano fishkeeping. Despite their tiny size, male Spotted Blue Eyes are among the most spectacular display fish in freshwater fishkeeping — the constant fin-fanning courtship display is mesmerizing to watch.
Feeding & Care Tip: Sera Vipan Baby is the ideal daily staple for this tiny species — crush lightly before feeding. Supplement 2–3× per week with Hikari Frozen or Freeze-Dried Baby Brine Shrimp, which are a perfect size for this fish. Feed small amounts 2–3 times daily. Competition at feeding time can be intense — ensure all fish receive adequate food.
Native to Aru Islands, Indonesia; northern Australia. This species inhabits slow-moving, heavily vegetated streams, billabongs, and swamps. Some populations occur in very soft, acidic blackwater while others are found in neutral water — the aquarium trade stock is generally adaptable to soft to medium, slightly acidic to neutral conditions.
Keep in groups of at least eight with a mix of males and females. Male display behavior is most active and spectacular in a mixed-sex group — males fan their elaborate fins continuously in competition for female attention. Keep only with other very small, peaceful species that will not outcompete them for food.
Blue-eye rainbowfish are best kept in a densely planted aquarium with fine-leaved plants and gentle filtration — strong currents will exhaust these small fish. They are most spectacular in natural-toned setups with dark substrate where the iridescent fin extensions and vivid eye color catch the light. Keep only with other small, peaceful species. Larger or more boisterous tankmates will outcompete them for food and space.
Care & Ideal Parameters
| Difficulty | Easy — Moderate |
| Temperament | Peaceful — Nano Community |
| Typical Adult Size | 1.2 inches (3 cm) |
| Min. Group Size | 8 minimum — mixed sexes for spectacular display behavior |
| Ideal Temp | 72–82°F (22–28°C) |
| Ideal pH | 6.0–7.5 |
| Ideal GH | 2–12 dGH |
| Ideal KH | 1–6 dKH |
| Staple Food | Sera Vipan Baby |
| Treat / Supplement | Hikari Frozen or Freeze-Dried Baby Brine Shrimp |
| Origin | Aru Islands, Indonesia; northern Australia |
| Notes | Males display elaborate spotted fin extensions — butterfly-like courtship fans. Keep with only small peaceful species. Aru Islands locality strains are most commonly available — see also Aru II and Aru IV listings for locality-specific forms. |
