Note: This webpage was reproduced from a cached copy of an article on the British Aquatic Resource Center website, which has disappeared. This article belongs to Kathy Jinkings, and no copyright to myself is implied. I have reproduced it on my site because it contains a nice photograph and good information on Rhinogobius wui. If anyone has information on where I can contact the author or the British Aquatic Resource Center, please email me.
One day while looking at fancy guppies in Pond Life (while they still sold tropicals) a movement at the bottom of the tank caught my eye, but I couldn't see anything there when I looked. Close examination revealed a tiny little brown fish, about ¾" long, that blended so closely with the gravel it could only be seen when it moved. Having spotted the little fish, I watched it for a while, and was entranced by it's strange bounding movements across the gravel. This was not, in my inexperienced opinion, the way fish ought to behave! This was my first introduction to a species of fish which proved to be small in stature but big in personality and appeal.
Enquiries revealed that the fish was a 'dragon goby' (be careful if buying these - this common name also applies to a huge purple thing that grows over a foot long!). They were five pounds a 'pair' so I bought a pair, and (being a regular customer) got a third one free. The tiny little fish were taken home and installed in a three foot tank with an assortment of other fish (guppies, bristlenoses, one sad neon, and everything else that had taken my fancy - this was in the days when I had a one-tank house!).
They settled in well, i.e. darted to the bottom and promptly became invisible. Searching for the gobies became a regular pursuit, and it often took a lot of searching before they could be found. Fortunately for my nerves, they grew rapidly, and found it a lot harder to hide when they were about 2" long. However, I was still unable to identify them properly (having looked up 'dragon goby' and come across the large purple one, which I was pretty sure they weren't.)
It wasn't until I paid another visit to Pond Life, and saw that one of theirs looked totally different that I realised that in fact I had three females (the picture in my book was of a male!). After making a nuisance of myself I obtained the single male at half price and took him home triumphantly.
Although the females are cute and interesting, they could not be described as particularly attractive, being nondescript gravel-coloured. The male, on the other hand, was spectacular when in full breeding colours (which turned out to be 90% of the time). The body is a dark chocolate brown, the dorsal fin is edged with red and white, and the throat is a brilliant red colour. This latter is not really noticeable until the male displays, when, like a frigate bird, he inflates his throat and throws his head back to display it to full advantage. Having seen a male, I couldn't believe how dim I had been not to realise that the previous inhabitants were all the same sex!
He settled in well with his harem, darting around the bottom, playing 'king-of-the-castle' on rocks, and displaying himself to his indifferent wives. Then, as I thought, tragedy struck. From being one of the most conspicuous tank inhabitants, one day he was nowhere to be seen. Removing all the plants and all the rocks which were on top of the gravel showed neither a fish nor a little corpse. Sadly I assumed he had died and become bristle-nose supper. I returned to the shop, to find they'd sold all theirs, and didn't know if they could get any more. This seemed to be the end of my goby-keeping.
Having searched so thoroughly, I was somewhat startled when about three weeks later he suddenly reappeared, resuming his old outgoing behaviour. This became a regular pattern - every month he would disappear for three weeks, and spend the other week eating anything he could get hold of (even flake, which he didn't like much and the females wouldn't touch) and generally behaving in a hyperactive way. I knew that he must be looking after eggs, but couldn't think where.
His secret was revealed, when I saw him digging a pit beside a small flat stone nearly submerged in the gravel. He would take a piece of gravel in his mouth, bound away and spit it out, making a little pile behind him. Now I knew what he was up to (and where) I observed him throughout the day. As the hole deepened, he began to move backwards under the flat stone, spitting the spoil from his tunnelling out the front. By evening all that was to be seen was a hole in front of the stone. By morning the hole had been filled in, the male was absent again, and the stone looked as though nothing could possibly be underneath it, being itself half buried in gravel.
After about a week my curiousity got the better of me, and I lifted the stone. Sure enough, there he was underneath, with a clutch of about fifteen eggs, transparent and colourless, and about 1mm in diameter. These eggs are attached to the underside of the stone above the male's hole (this must have taken some acrobatics in such a confined space). Each egg has a little 'stalk' which attaches it to the stone - this stalk end eventually becomes the tail end of the fry - usually.
In this case no fry developed, as I removed the eggs and attempted to hatch them artificially, as I was afraid the new fry would be eaten. Within a day all the eggs had fungused. The male, during this time was thoroughly upset about the sudden disappearance of the eggs. For several hours he sat disconsolately where the stone had been, occasionally looking under stones in the immediate vicinity, and sometimes digging in the gravel. He did slowly lose interest, but it took a surprisingly long time (about a day) before he gave up totally and stopped returning to poke around in the hole.
This procedure was repeated with a number of variations - methylene blue in the water, aeration directly under the eggs, regular water changes, no water changes - every variation possible. I have found it to be impossible to hatch the eggs artificially from an early stage.
So finally, I decided to leave the male with the eggs to see if he could do better. He could. I knew that he usually reappeared after three weeks, so after about 18 days I lifted the stone. What looked like a cloud of little slivers of fry darted out into the waiting mouths of the other tank inhabitants. Another failure!
To cut a long story short, trial and error revealed that the gobies hatched on the fifteenth day (at between 75F and 78F). By removing them on the fourteenth day, the fungus can be prevented with strong aeration (even at this late stage, while wriggling to escape the egg sacs, they will still fungus without a strong aerated current), and the fry can be saved from becoming a tasty meal for another fish (including their mothers!).
The fry are colourless, with tiny black pin-prick eyes, and about 1/2cm long. They hatch while still attached to large white translucent egg yolks, and have no interest in food until these have been absorbed. This happens by about the third day, when the fry develop a ravenous appetite for brine shrimp nauplii, and after a good feed their distended bellies are a bright orange through the still colourless skin. They have absolutely no interest in flake or liquid fry food, and will starve to death unless fed live food. As they grow the addition of some flake (finely ground) will tempt them, and fry raised with a little flake will continue to eat it in times of emergency. Their natural diet is live food though, and unless fed either live or frozen food they will not do well.
Within about a week the fry start to colour, and rapidly progress to the gravel colour of their mothers. The males do not start to get their full colouration until about an inch long.
These are peaceful, small fish (females about 2", males about 1.5" at full size) and make ideal inhabitants for a community tank, although if more than one male is kept they need about a square foot each to themselves. They neither attack anything (except guppy fry, which the full size fish relish) nor are attacked because of their habit of keeping out of the way at the bottom ( although I suspect a predatory nocturnal catfish would find them pretty quickly). They enjoy hard water, and provide continual amusement and entertainment by their bounding movements in the bottom of the tank. I would recommend these gobies to anyone.
It is, therefore difficult to understand why they appear in shops so rarely. I have not seen any for sale in a fish shop since I bought mine. They are, however, freely available through clubs and auctions, and once you've had a pair, a little care will ensure you have a continuous and ever-growing family of them!.