two to five. They usually stay close to the edge of the water, in the shade of overgrown shore vege-
tation. Both species look very similar and have a similar reproductive strategy. Their cherry-red
eggs, which are usually attached individually to the vegetation (Evers 2012), are very striking. We
never found either P. pellucidus or P. novaeguineae in any other type of water.
Some of the waters encountered in this area, such as the Kali Kopi (kopi means coffee in the
Indonesian language), are almost coffee-brown during times of low rainfall. The springs of these
mostly small rivers bubble up from sand and gravel from the nearby mountains. The water is full
of leaves, which turn the water dark but, unlike the eroded quartz of classic blackwater springs,
add minerals. Therefore, this is not typical black water.
The pH values of these streams are always in the neutral to slightly alkaline range, with
relatively high electrical conductivity (Kali Kopi on February 16, 2017: 65 μS/cm, pH 7.5,
85.4°F/29.7°C). The third blue-eye, P. ivantsoffi, inhabits clear water and was documented along
with P. pellucidus. The species also occurs much more frequently in blackwater marshes and their
slow-flowing outlets.Variants
In the hobby, we recognize variants of Ivantsoff’s Blue-Eye that differ in size and finnage. I have
found that specimens from clear, fast-flowing rivers grow larger and stronger (up to 2.8 inches/7TOP & MIDDLE: H.-G. EVERS; BOTTOM: F. WANG
AMAZONAS
This male Pseudomugil novaeguineae from Timika
has a lot of red on the lower posterior half of his body.A male Pseudomugil pellucidus “Kiura.”A displaying male Pseudomugil sp. “Red Fin.”