SOME SPAWNING OBSERVATIONS ON MORGUNDA GOBIES

By David Marshall, Ryedale Aquarist Society

.The bethnic goby genus Morgunda is endemic to Australasia. Here they inhabit freshwater rivers; sinkholes and jungle pools were they make the most of whatever form of natural cover is available. In the aquarium hobby the species most commonly seen is Mogurnda mogurnda (the Purple Spotted Gudgeon).

Upon receiving a pair of M. mogurnda, from Kevin Webb, I set about a breeding programme but the fish beat me to the post and spawned in a community tank. Here are my notes on what occurred: -

On Tuesday 1/7/03 I noticed, to my surprise, that my mature pair of Mogurnda mogurnda were checking out an area of glass in the front left-hand corner of their tank (in the wild they spawn in small crevices). Suddenly the female lowered her ovipositor and began to paste eggs, in several small batches, upon the glass (very similar to the spawning of Jewel Cichlids). The male was quick to follow her moves and spread milt over these eggs, which would eventually total around 140.

As Kevin had explained to me the eggs are attached to the glass on tiny shreds and move about like those of marine Clownfish. As soon as they realised that spawning activity was over the rest of the tanks residents, spearheading their advances through a Bulldog Plec. moved in for their share of fresh caviar. Something very strange happened at this point as any fish getting close to the two mature Mogurnda usually pay for their audacity with a quick 'nip to the flanks' but on this occasion (probably through breeding shock) they simply stood aside as their eggs were assaulted.

I acted quickly removing around 40 eggs and placing these into a water filled shallow plastic container, which was then floated in a spare tank. I didn't add a trickling airstone or any Protozin and this might have been a big mistake?

By the morning of 3/7/03 some eggs had fungused (quickly removed), some were clear in colour while a few were showing a small black streak over a yellow centre. The shape of the eggs was clearer to see now and their resemblance to the shape of the egg cases of a Port Jackson Shark was astonishing (of course, though, they were much smaller).

By evening some of the egg cases have broken open and the tiny black streaks are fish skeletons minus a face. 3 viable eggs, attached by their shreds to the sides of the container, remain. Their skeletons are curved over the yellow centre and have eyespots now.

By the afternoon of 4/7/03 the 3 eggs had all increased in size and, as a result, you could see the growth of the 3 fry inside also taking place.

On the morning of 5/7/03 a fry had tried to break clear of its case but must have been very weak as it had died in the effort. By afternoon the remaining two cases were empty and their fry were sat on the base of the container. It had never dawned on me that the large yellow centre of the eggs was a huge, in comparison to the fry atop them, yolk sac.

Sadly I would find both fry dead the following morning. At least I had witnessed a spawning of this particular fish and made some interesting notes on the eggs that add to our knowledge of these very peculiar creatures.

Aquarists' able to take things a stage further were able to raise fry by first feeding the micro-organisms found in green water, followed by live brine shrimp and, finally, crushed flake. Cannibalism amongst the fry is high.


 

Acknowledgements
Thanks to John without
his help I could not have made this site