AAGB

Spawning Parosphromenus anjunganensis

by Kevin Marshall

In early August 1993, I was fortunate enough to see displayed for sale, aParosphromenus species. Although marked as P.deissneri, it was not until they settled in their new home that I could see that they, in fact, fitted the description outlined in 'Labyrinth' 62, for a newly-described species,P.anjunganensis, from Kalimantan (Indonesian Borneo). The fish are extremely attractive, male and female both show the typical tan and brown-striped markings on the main body. Sexual differentiation is difficult but given ideal conditions, the differences become apparent. Males show a solid red colour in the dorsal, anal and caudal fins, with a fine crystal-blue outer margin. The ventral fins are blue. Females sport a similar colour scheme but lacked the depth and intensity of the male.

A pair were housed in a 3.5 gallon aquarium, furnished with fragments of terracotta plant pots and upturned coconut shell. No gravel substrate was included, although groups of stone were arranged to give additional cover, as were fronds of Java fern and Java moss. In spite of using a small corner filter utilising aquarium peat and filter wool, the pH remained neutral while the temperature was maintained at 78F.

The fish, although shy, had settled down within a short space of time and their behaviour strongly indicated that they were a true pair and although still juvenile, the male would display to the female and try to entice her into a suitable spawning site. All his attempts however, remained in vain.

To obtain a successful spawning, I was well aware that I would have to lower the pH of the water considerably. This problem was to be solved by pre-treating water which filled a collapsible water carrier. A generous amount of aquarium peat was added and allowed to steep for a few days, after which a pH of 4.3 had been achieved. I had intended to carry out a number of water changes in order to bring about a gradual reduction in pH but after several water changes, the pH was unchanged. Questioning the inertness of the terracotta plant-pots and stonework, I decided to remove them, also for good measure I changed the filter medium for some fresh peat. A 50% water change was carried out using the pre-treated water which was added gradually, to prevent unnecessary stress on the fish.

The effect was noticeable overnight and whereas before I had thought that the fish had appeared well enough, they now positively radiated health. The male was resplendent in breeding colours and recommenced to court the female within a couple of days. She had lost her striped patterning and had become uniformly brown with the fins showing a reddish tinge. An egg spot was also seen, protruding from her papilla.

On 21.09.93, I discovered that a spawning had taken place. The spawning site was a cave formed by a fragment of coconut shell at the front of the aquarium. A pH reading gave a value of 5.1. The male was n attendance at the nest and had driven off the female, who was still close at hand and was showing a slight interest in the nest site. Her approach, however, was not tolerated by the male. Although a few of the large opaque eggs could be seen in the roof of the cave, no nest was apparent until the next day. By this time the male could also be seen venturing to the surface, to collect air bubbles to add to the nest. It was also noted that, during the following development of the eggs, the male remained very attentive, constantly fanning and mouthing the eggs.

By Friday, 24.09.93, the fry looked more fish-like. It was not until the following day that the young fishes' eyes were apparent. The female remained in the aquarium and now actively sought out the male who had begun to be more tolerant of her presence at the spawning site.

On the morning of 29.9.93, the male was observed taking air bubbles into the cave. By mid-day spawning occurred, both fish embracing in typical fashion and the eggs sank to the floor of the cave. Both fish took an active role in retrieving the eggs and placing them on the roof of the cave. By 7 p.m., spawning was complete and the female was driven from the cave. The nest now contained both fry and eggs, although some fry were beginning to stray, only to be collected and returned. The constant activity seemed to be to much for the integrity of the nest, which appeared to have collapsed.

On 30.09.93, some 24 eggs could be seen on the floor of the cave, along with fry scattered throughout the cave. By 1.10.93, few fry could be seen and the eggs were in disarray. At this point I thought it wise to remove the male. The eggs were duly siphoned into a 1 pint glass jar and hatched artificially. Fry from the first spawning were now free-swimming and ranged throughout the aquarium and could be seen, hiding in the foliage and attached to coconut shells. They readily accepted newly-hatched brine shrimp and were weaned onto microworm.

Development of the second spawning followed a similar pattern and they were free-swimming by 9.10.94, when they were allowed to join their older siblings. At this point the total number of fry was estimated at 20. Although the fry remained very shy, their subsequent care and rearing posed no problems. As for the adults, spawning continued, pretty much on demand. However, my initial success was not to be repeated, with eggs disappearing by the second day even though great care was taken to carry out brief periods of observation and to shade the aquarium from bright light and external distractions.

An attempt to hatch the eggs artificially, also met with limited success with only 6 fry hatching from a clutch of some 125 eggs.

Because of the demanding nature of these fish, I found that, in achieving some small degree of success, the results paid back are definitely worth the effort put in!

Back to articles