The Spotted Blue-Eye By John Fleuren
The spotted blue-eye, Pseudomugil Gertrudae for those with a liking for scientific names, is a delicate looking fish of about 30mm standard length when fully grown. They are basically a silvery standard looking fish with small black spots all over their body, dorsal, caudal and anal fins, whilst the pectoral and pelvic fins are clear with a hint of yellow and white. As for any blue in the eyes, well I couldn't spot any but then again I may be colour blind. The fish is sexually dimorphic in that the male is slightly more colourful and has extended rays in the ventral, dorsal and anal fins (most noticeable in the ventral fins.
Blue-eyes (the fish, not the singer) were once grouped amongst the Australian and New Guinea rainbow fishes (Melanotaeniidae), but recently have been re-classified to their own family (Pseudomogilidae) that contains some 10 species. This reclassification I understand is due to the fact that they are more closely related tot he ancestral Melanoteaemiid stock. Spotted blue-eyes are fairly common and according to Fresh Water Fishes of Australia (by Dr G.R.Allen) are found in those small creeks swampy marches, lily lagoons etc located at the 'top end' of QLD and the NT.
Digressing just a little from the main topic, my main fresh water fishy interest has been and still is with various tetras and South American dwarf cichlids. Sure, I have heard of, and seen, various types of rainbows during my many years in this hobby, but never believed they could measure up to the brilliance of tetras like the cardinal tetra or the diamond tetra. That was until I saw some slides of the neon rainbow at a CDAS general meeting; this fish truly is a sparkling beauty that I can highly recommend as a tetra alternative. It wasn't long before I obtained some of these fish and became hooked on small rainbows. I asked around if anybody kept any other smallish rainbows and as a consequence was very generously offered a few different kinds including these spotted blue-eyes (an offer too good to refuse). SO thus I ended up with 5 of these cute little critters.
Back to blue-eyes. Being a small fish they do not need a big aquarium, mine went in an 18 inch tank holding approximately 18 litres of water. Aged water from my tetra tank was used (pH 7.2; TDS 120 ppm; total hardness 5DH). Furnishings are sparse with a clump of Java moss, a few bits of Java fern, and the all important spawning mop. Also, a small air powered sponge filter maintains water hygiene and a 25 watt heater-thermostat keeps the temperature at about 26 degrees Celsius.
After only one day in their new home I found a couple of eggs in the spawning mop, and this scenario of a few eggs a day has in fact become more or less the norm. Work commitments so far have prevented me catching them in the act of spawning, but one day I will (maybe). The eggs are fairly large, transparent and quite tough. I collect them every day or so by picking them off the spawning mop. The mop gets a good squeeze first to remove most water, making the eggs stand out by looking like little water drops. They are incubated in small drinking glasses that are floated in another small tank (this one only holds about nine litres of water). The glasses are filled with about 20mm of water from the parent's fish tank.
Waiting for eggs to hatch is a lesson in patience, in fact after two sveeks and no sign of any fry I thought the whole thing had become a miserable failure. But I was told to hang in there as it could take three weeks or more for the eggs to hatch. A long 22 days later, the first fry appeared. They seem to be free swimming as soon as they hatch, and hence require immediate feeding (no sign of any post hatching yolk sack as far as I could tell). Since the eggs are transparent it would be quite easy to observe the development of the fry with the aid of a good magnifying glass.
As soon as the fry hatch, I spoon them out of their drinking glass and transfer them into a feeding tank (also about nine litres). The fry are fairly small and initially are fed with dust foods like micro encapsulated 'artificial rotifers' and sera micron fry food. After a week or so this first food is supplemented with vinegar eels, and several weeks later, the initial fry foods are replaced by micro wortms and occasionally some baby white worms.
The fry grow very slowly (once again patience is a virtue), after 15 weeks the biggest measured about 12 mm and at this growth rate it would take at least seven months before they reach a decent size.
All in all, the breeding effort over some four months has resulted in about 50 tiny spotted blue eyes. I don't know if that's a good effort or not, but personally I am delighted with the results and that's what this hobby is all about.
Next I hope to try my luck with some honey blue-eyes as these are currently in danger of becoming extinct in the wild. If they are anything like the spotted blue-eyes the rewards in propagating this species will be even more rewarding.
As a summary, the spotted blue-eyes is a small and very interesting Australian native fish that needs only a small tank, requires no more care that the average tetra, and can be bred very easily provided you can spare a few drinking glasses, a couple of bookshelf tanks and a bit of patience. Ergo the spotted blue-eye is an ideal aquarium fish that deserves to be hugely popular.