MEET THE GOBIES
Usually considered a saltwater staple, gobies have many freshwater cousins suited to life in the home tank. Here are three of the best…
Introducing three freshwater species of goby perfectly suited to life in the home aquarium.
The beautiful Bumblebee
ONE GOBY that’s been conservative with its movement from marine to freshwater habitats is the Bumblebee goby, Brachygobius
doriae. Many freshwater gobies are coastal inhabitants in freshwater but the bumblebee is amphidromous, exploiting fresh and salty habitats – and many live in brackish bodies of water. Bumblebees live together in colonies, mostly over muddy substrate and overlaying organic matter – leaf litter, seed pods and driftwood, for example. Those found in mangrove areas are the ‘salty’ dwellers, but there are also populations of Bumblebees that live in dark and tannin-stained peat swamps.
Colonies are well organised. Males are highly territorial towards each other but there’s no aggression if each sticks to his patch.
It’s not easy to identify the sexes. Sexually mature females have a slightly rounder body when viewed from above, but there’s nothing else to go on beyond social behaviour, where males are more accepting of females within a territory. Ideally you should aim to keep
B. doriae in a species-only tank, although a taller tank of 45cm depth or more could house some small, non-aggressive brackish tankmates higher up in the water column – such as the Wrestling halfbeak, Dermogenys pusilla, or Cayman limia, Limia caymanensis, if you can find them. As the gobies inhabit only the substrate layer and rarely swim any higher than an inch or two, there should be no territorial overlap.
Despite the diminutive size, their character and courage are both vast. Keepers routinely note how they come to the glass to defend their territory and even attack fingers during tank maintenance. Some owners have got Bumblebees to accept flake foods on occasion, but mostly they need frozen or live insect larvae and shrimps. Food items needn’t be small, as they’re quite happy to tackle meals half their own body size.
In the Stiphodon genus, adult fish are pure freshwater dwelling, but larval fish need to be washed down river into the sea for development among the abundant marine plankton found there. Once complete, the young fish find their way back upstream and switch back to a freshwater existence.
They are found in coastal rivers of differing flow rates. Species with smaller dorsal fins tend to inhabit fast-flow rivers and streams and often site themselves around waterfalls, which they can – and will – climb. Species with showier, extended dorsal fins like the Rainbow stiphodon, S. ornatus, come from waters that run more slowly, though they still have ample flow and levels of dissolved oxygen in abundance.
The Rainbow stiphodon and the Blue neon goby, Stiphodon
atropurpureus, are by far the most commonly found in shops, though you may find Red-coloured stiphodons with a bit of luck. These aren’t the easiest fish to identify as many species share similar markings and even colours. Even patterns can change in synch with their moods, so a fish may look like one species one day and another the next.
The fish you see in the shops are wild caught, and while there are accounts of courtship and spawning, fry haven’t been successfully reared so far. Wild stocks face some pressures. Not only is there a noted effect on numbers from collecting for the aquarium trade, but they also face the ‘common three’ issues of habitat degradation, pollution and the introduction of non-native
species, such as Tilapia.
In aquaria they must be provided with clean, well-aerated water, ideally with strong flow and lots of rocks. Slate pieces laid flat imitate their natural bedrock substrate, while rounded pea gravel and different sized cobbles complete a naturallooking tank and offer lots of feeding surfaces. There’s evidence that different species of the genus covet certain-sized stones, so giving them a choice may well help.
Stiphodon feed mostly on aufwuchs (micro fauna and flora growth) from the rocky surfaces. There are a few supplementary foods suitable, one of which is Soilent Green paste food by Repashy. Small amounts of frozen or live meaty foods can be offered but keep it minimal – the richness can be a problem for what are mainly vegetable grazers.
Aufwuchs can be encouraged to grow easily – running aquarium lights for longer than normal (10-14 hours a day) will get them going. If this isn’t enough to sustain them, then leave some cobbles immersed in water in a bright spot in the garden, and aufwuchs will form on them.
Stiphodon are remarkably peaceful, so all you need are peaceful tankmates that can handle the increased flow, don’t outcompete the gobies for food, and don’t disturb them with constant activity. Avoid the likes of active botiid loaches and larger, flow-loving tetras like the African red-eyed, Arnoldichthys
spilopterus. Instead, consider the Rosy loach, Petruichthys sp. ‘rosy’, Glowlight danio, Danio choprae, or White Cloud Mountain minnow, Tanichthys albonubes.
Rhinogobius is a genus quite far removed from its marine heritage. Yet, like Stiphodon, a few
Rhinogobius species release their larvae to be washed out to sea to grow large on plankton before returning to freshwater – though these aren’t the species you’re likely to find on sale.
Of the 65 valid species, those you are most likely to meet come from the Rhinogobius duospilus complex (duospilus is both a species name and a group of species). These land-locked, Chinese fish live only in freshwater and they are by far the most common. Not that they’re always readily available, however. Finding some types can
involve some real effort. One way to source the more unusual varieties is to peruse social media groups dedicated to gobies or Rhinogobius themselves, where you may even be able to find captive-bred specimens.
They are interactive fish and heavily food focused, which makes feeding time an absolute pleasure – especially if they’re getting live foods! They will accept most frozen foods, but noses may still be turned up at some; safe bets tend to be worm types and brineshrimp. Offer live foods at least weekly, some of which can be cultured at home. As a pro tip, chopped earthworms go down particularly well.
‘Flaring’ is something you’ll see regularly with any Rhinogobius species. By opening his mouth wide and stretching his neck, the male gives a sign of dominance and willingness to defend a territory from other male tankmates. You can keep a male and two females in only a 45cm tank, but you’ll get much more entertainment from keeping two males and four or five females in a 60cm/70 l set-up.
The tank will need strong flow with lots of rocks around the base. These will create small territories and break up the line of sight for whenever a dispute takes place. Note that Rhinogobius species are diggers and will excavate around rocks, so position larger ones on the base of the tank (or on protective egg crate) to avoid landslides and to prevent the gobies getting squashed.
For chemistry and temperature, they’re pretty easy going, preferring slightly alkaline, cool conditions. Suitable tankmates will hinge on how hot you run the tank. For an unheated tank that may drop below 20°C, then choices are slim – White Cloud Mountain minnows,
Tanichthys albonubes, Glowlight danios, Danio choprae, or Zebra danios, D. rerio, would suit.
With a heater set to low 20°Cs consider smaller rainbowfish – Dwarf neons, Melanotaenia praecox, and Macculloch’s rainbowfish,
Melanotaenia maccullochi. Tetras like the Dawn tetra, Aphyocharax paraguayensis, and Glass bloodfin tetra, Prionobrama filigera, would also work. Avoid other bottom dwellers because of the territorial behaviour of the Rhinogobius.