Pseudomugil cyanodorsalis

Pseudomugil cyanodorsalis, commonly known as the Neon Blue-eye, is a small and strikingly colorful fish species found in coastal waters of northern Australia and possibly southern New Guinea. Let’s dive into some details about this fascinating aquatic creature:

1. Etymology:

   • The genus name, Pseudomugil, combines the Ancient Greek word “ψευδής” (pseudes), meaning “false, lying, untrue,” with the generic name “Mugil.”
   • The species name, cyanodorsalis, is derived from the Ancient Greek “κυανός” (kýanos), meaning “dark blue,” and Latin “dorsalis,” meaning “of or pertaining to the back.” This refers to the coloration of the upper body in this species.

2. Distribution:

   • The type locality for P. cyanodorsalis is Crab Creek, approximately 15 kilometers east of Broome, Western Australia.
   • However, this species appears to be widely distributed in coastal waters of northern Australia and potentially southern New Guinea.
   • It tends to be locally abundant and forms large aggregations when present.
   • Populations are often labeled by enthusiasts to prevent cross-breeding.
   • It has been recorded in various locations, including close to Broome and Wyndham in Western Australia, around Darwin in the Northern Territory, and in Queensland’s Norman River.

3. Habitat:

   • P. cyanodorsalis is euryhaline, meaning it can tolerate significant fluctuations in salinity and other water conditions.
   • It inhabits both full marine conditions and pure freshwater environments.
   • Common habitats include coastal mangrove creeks, swamps, and areas influenced by daily tides or seasonal changes.
   • Substrates are typically composed of silt and mud, with cover provided by marginal vegetation or submerged mangrove roots.
   • Interestingly, it can be found living sympatrically alongside its congener, Pseudomugil inconspicuus.

4. Physical Characteristics:

   • Maximum Standard Length: 30–35 mm.
   • The males exhibit striking coloration:
     • The upper half of their body is metallic blue, similar to the Neon Tetra.
     • The lower half is translucent to yellowish-white.
   • Females are generally less colorful but still attractive.

5. Aquarium Care:

   • An aquarium with base dimensions of 45 cm × 30 cm or equivalent is suitable.
   • Water flow should be around 4–5 times the aquarium volume.
   • Opinions vary on whether it requires salt, but maintaining it in brackish conditions tends to promote better health and longevity.
   • Specific gravity between 1.001 and 1.010 is recommended.
   • Aquatic plants are usually absent, but cover from marginal vegetation or submerged roots is beneficial.