Spawning the Blue-Eye Rainbows

By Jeff Michels

The blue-eye rainbows from Australia and New Guinea are truly something to behold. There are currently fifteen described species in the genus Pseudomugil with others sure to be discovered. Most of the dwarf rainbows in this genus are found in coastal rivers and streams which will contain anything from very soft acidic water during the rainy season to the extreme opposite values with near sea water pH and hardiness values with some salt thrown in for good measure. Measuring in at an average of 1" in length and in a few cases reaching over 2" total length make the blue eyes truly a dwarf by rainbow standards.

The spotted blue-eye hails from northern Australia and southern New Guinea. Males of this 1 ½" fish sport black polka dots over all their fins except the pelvic and pectoral. The very tips of the pectoral fins are white, yellow, orange, or even a light blue depending on the collection location. The females lack the spots and colored tips on their pectoral fins and resemble the males only in body shape, a long torpedo build, and with each grey scale being edged in black. And of course both fish have bright blue colored eyes.

P. signifer is found all over the western coast of Australia in streams and estuaries. With its gigantic distribution comes variation with at least 15 different color or fin variants easily recognized. The most sought after location for this rainbow is Harvey Creek. This location has a signifer that has bright yellow unpaired fins edged in black which boast a vertical spread that is as tall as the fish is wide. It is a truly awesome animal. The more commonly encountered variety comes from Cross River. This form has a much shorter fin spread with orange colored unpaired fins edged in black with a white tip. The eyes of all the locations are true to their name and a gorgeous shade of blue. At a maximum size of about 2 ½" long this blue-eye is one of the largest in the genus.

Breeding

As with all rainbow fish, P. gertrudae and P. signifer are egg laying fish that use an algae or plant mass as their spawning media. Several large eggs are laid in the plants or yarn spawning mop almost daily. The laying of eggs is proceeded by the male vigorously displaying to the female by swimming in front of her and erecting his fins.

The first time I realized that these rainbows would be easy to spawn was when I saw a baby in the gertrudae tank. A new born blue-eye closely resembles a sliver floating just under the surface of the water. These babies are tiny. So tiny in fact that they can’t eat baby brine shrimp for over a week. I left the first baby to fend on his own, feeding off of the microorganisms in the java moss. All of the future eggs laid have been collected and raised by themselves. That first baby turned out to be a male who has joined his parents as part of the small school of breeders.

I’ve found that picking the eggs out of a yarn mop is much easier then locating them in java moss. A side note, green yarn seems to reveal the eggs better then black dose, at least for me. As the eggs are collected I place them in a small butter dish containing about ¾" of water from the adult tank, which is Milwaukee tap water. This water is lightly bubbled, 1 to 2 bubbles per second, to keep it from becoming stagnate. I also like to keep a small piece of java moss in the butter dish to help keep it cleaner and give the babies an added food source. The eggs take 10 to 12 days to hatch at 80F. Now here’s the big secret to get the eggs to hatch, I add a few drops of marine salt water to the butter dish. The added minerals seem to aid in development and the actual hatching from the eggshell.

The young rainbows then spend the next two weeks or more in the small dish being feed O.S.I. micro-food two or more times a day. The small hatching container aids in getting the food to the small fish and increases their growth rate. After two weeks the fry are moved to a 2 1/2gal tank with a sponge filter were they are feed both the micro-food and baby brine shrimp.