Usu­ally con­sid­ered a salt­wa­ter sta­ple, gobies have many fresh­wa­ter cousins suited to life in the home tank. Here are three of the best…

Practical Fishkeeping (UK) - - Contents - WORDS: STEVE BAKER

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.

Smash­ing Stiphodon

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.

De­light­ful dragons

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.

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