Australian Native Fishes

by Peter J Unmack

Australia has a relatively depauperate fish fauna for it's given size with approximately 200 species from 35 families. Despite the lack of species many of them make excellent aquarium fishes. Most of the families that I discuss are found over most of northern Australia which means everywhere except the cooler south-west and south-eastern coastal region which is more temperate in nature.

Most of the species found in northern Australia will tolerate temperatures between 60 and 90°F. Generally I prefer to keep most at around 74-76°F. Don’t be afraid to give the fish considerable seasonal variation in temperature (albeit slowly), most of my fish are kept at whatever room temperature was unless I was trying to spawn them. Most Aussie natives require no special water conditions. Australia can have quite large changes in rainfall between years. As a result, fish often go through droughts or dry seasons where the salinity, hardness, and other dissolved salt levels become quite high due to evaporation. Conversely, when rivers flood the quantity of dissolved salts in the water is very low. Thus, do not worry if your Aussie fish are at 20 ppm or 300 ppm calcium/magnesium hardness, it is not very important. Every species that I know of has quite high salinity tolerance. I usually treat diseases such as whitespot and fungus with 10ppm of cooking salt (10 grams/litre or about 1 1/2 ounces/US gallon of straight Sodium Chloride, not table salt); most species should tolerate 17 ppm. I would usually add 10ppm of pre-dissolved salt over a few hours, although the speed at which the salt is added is not very important. However, the fish must be allowed to slowly acclimate back to freshwater at probably only a 30-50% rate salinity decrease per day. Many species can also tolerate naturally occurring highly acidic conditions such as those caused by tannic acid from rotting plant matter which occurs in the dry season. I have personally seen rainbowfish at a pH of 4. In fact, many rainbowfish show their best colors in tannic acid (it usually leaches from driftwood placed in the aquarium), although they generally will not spawn in acidic conditions. However, please note that if this was nitric acid caused by poor water quality the same fish would probably be dead. Aussie natives are fussy though about having good quality water, to keep them looking good and happy large regular water changes are a necessity. I have often seem people have problems with Aussie natives (such as rainbows that break out in tumors) that are kept in tanks with a high organic load. By this I mean too much fish crap. I usually change 80% of the water and at the same time gently clean the filters out in the same water I remove from the tank. This is to reduce the loss of bacteria (I had small removable undergravel filters). I would then top the tanks up over 2 or 3 hours with water that was usually over 57 °F. I never had any ammonia problems when cleaning the filters this way at the same time as doing a large water change, even in heavily fed over crowded tanks.

In my experience most Australian fish will not eat prepared fish foods such as flakes and pellets. Most species do best when fed “real” food. By “real” I mean unprocessed foods such as frozen brine shrimp, blood worms, or pieces of raw fish and any live foods that you can obtain. A number of Aussie fish like some vegetables so do not be afraid to try peas, spinach, or any of the usual parboiled green foods as well as live veggies such as wollfia or duckweed. Some groups such as rainbowfish, blue eyes, and hardyheads will eat ordinary prepared foods, however they really do best when fed “real” food.

The following is a summary of the more important Australian groups which are amenable to being kept in aquaria. The common and scientific name/s of the family are given followed by the number of species present from each family in Australia.

Arowana, saratoga, bony tongues Osteoglossidae: 2 species: Nobody in Australia refers to the local species as arowana’s. Both species grow to 3 ft and are mouth brooders. Saratoga (Scleropages leichardti) lack chin barbels when smaller than 5 in, this distinguishes it from gulf saratoga (S. jardinii) which always has barbels, I am not familiar with how to separate larger fish. As far as I am aware their aquarium care is similar to other arowanas. Saratoga can tolerate lower temperatures (60 °F) than gulf saratoga (~70°F). Like other arowanas, the Australian saratogas are mouth brooders with the eggs carried by the female.

Archerfish Toxotidae 3 species: The most common species is the seven spot archerfish (Toxotes chatareus) which is found over much of northern most Australia and also throughout much of Asia. This species lives and breeds in both fresh and brackish water. The remaining two species are far more restricted in distribution.

Forked tail catfish, salmon tail catfish Ariidae: 5 species: They are found at low altitudes over most of northern Australia. Most of them can live in either fresh or brackish aquariums. Some species may grow to over 40 lb (eg, Arius midgleyi). They are quite peaceful, although because of their size they should only be kept with larger fish to avoid them eating anything smaller fish. They make excellent sport and eating fish although most people avoid them because they are put of by their appearance or they are trying to catch other “more desirable” species. Forktail catfish are a hardy group which can tolerate very broad conditions and are excellent scavengers. Forked tail catfish are mouth brooders, the male carries the eggs after they are fertilized. To the best of my knowledge they have never been spawned naturally in captivity.

Eel tailed catfish Plotosidae: 11 species: Eel tailed catfish are found over most of Australia, although all but a few species are relatively restricted in range. Some only grow to 6-8 in and live in desert hot springs while others may reach up to 3 ft and 15 lb. They make excellent aquarium fish being generally quite peaceful, hardy, and they will eat almost anything. Be warned though, a large catfish would be quite comfortable eating smaller fish. One species that I have found to be a little aggressive at times is the freshwater catfish (Tandanus tandanus). Most catfish make excellent eating, though most people prefer not to catch them for various stupid reasons. Only the Dalhousie catfish (Neosilurus sp.) has been spawned in aquaria without the aid of hormone injection. Most species appear to be egg scatterers, although members of the genus Tandanus build a nest and guard the eggs until they hatch.

Giant perches Centrapomidae 1 species: This is the famous barramundi (Lates calcarifer) that grows so big that Crocodile Dundee had to use a shot gun to catch them! An excellent sport and eating fish which occurs over much of northern Australia. They grow to about 4 ft and 130 lb. Smaller specimens make fantastic aquarium specimens, especially for getting rid of goldfish and other trash like cichlids. They usually spawn in estuaries where they release several million pelagic or floating eggs. Most males once they reach 5 years of age have changed into females.

Hardyheads, silversides Atherinidae 14 species: This group is found throughout northern and central Australia, although each species is generally restricted to a particular region. They make excellent aquarium fish. While they are not as colorful as rainbows, they do go an attractive yellow color on the lower body surface when aroused. Generally they can grow to 3 in and are easily spawned, although most species have never actually been kept or spawned in captivity. Most aspects of spawning and raising fry appear to be similar to rainbows. I usually maintain the temperature over 78^°F to spawn the fish. From the couple of species I have spawned females appear to lay slightly fewer eggs than most rainbows. They readily spawn on mops. I usually start the fry on vinegar eels until they are large enough to eat brine shrimp. Fry typically grow slowly. One species, the Lake Eyre hardyhead (Craterocephalus eyresii) can survive at salinities ranging from zero to 110 ppm (just over 3 times the salinity of the sea or over 1 1/2 lb of salt per US gallon!). I have also observed the Dalhousie hardyhead (C. dalhousiensis) making very brief excursions from water at 104 °F to 108 °F, one of the hottest voluntary temperatures that fish have been recorded at anywhere in the world!

Glass perchlets, chanda perches Ambassidae 8 species: Comments are identical to hardyheads except that the fry are smaller and harder to raise. Despite the fact that very few people keep them in aquaria they do make excellent aquarium fish.

Rainbowfish Melanotaeniidae 13 species, 4 subspecies: Rainbowfishes are the glamour group of Australian fishes. They are found throughout most of Australia except the coldest regions. At least an additional 40+ species occurs in New Guinea and more are regularly being discovered such as the latest gem Melanotaenia praecox. In my opinion, rainbowfishes are one of the easiest of the world’s fish groups to breed in aquaria (with some exceptions though). Most rainbows will spawn at temperatures over 78 °F. Other than the fact that fry are slow growing they are not particularly difficult to raise. Some rainbowfish are surprisingly tolerant of cold conditions. I have personally had desert rainbows (M. splendida tatei) that I have collected survive overnight temperatures as low as 43 °F without signs of stress.

Blue eyes Pseudomugilidae 7 species: These sparkling little species are quite similar to killifish in their small size, attractive coloration, and low fecundity. They are found over most of coastal northern Australia. One species, the red-finned blue eye (Scaturiginichthys vermeilipinnis), lives in desert springs where the water temperature goes up and down by up to 38 °F daily. It also is the smallest freshwater Australian fish and it has the longest scientific name of any! Most species grow no more than 1-2 in and they generally live for up to 2 years. Blue eyes tend to lay very few large eggs daily and are best spawned in small groups, especially if you wish to breed larger numbers of them. The fry are raised in a similar manner to rainbows. Blue eyes are a brilliantly colored and very dainty group of fish which deserve far greater attention from aquarists.

Cods and perches Percichthyidae 8 species: This group contains the Murray cod (Maccullochella peelii), Australia’s largest freshwater fish. It grows to 6 ft and 250 lb. Cods and perches mainly occur in south eastern Australia with one species in Western Australia. Every species except one grows larger than at least 18 in. This group is one of my favorite. They are delightful fish that should only be kept by themselves. They are very popular angling species which make great eating (so you thought trout were good to eat--wait ‘til try these guys!). Because of their size they require a large tank. It is not feasible for the home aquarist to breed these fish as they all require hormone injection. Golden perch (Macquaria ambigua) are one of the few freshwater fish in the world which lay fully pelagic eggs (floating eggs). Up to 1 or 2 million eggs are produced per large female. They also have one of the longest recorded fully freshwater migrations known among freshwater fish. They have been found to swim at least 1200 miles in 18 months completely within freshwater. This group of fish is incredibly friendly towards their owners and they love to devour copious quantities of trash fish.

Grunters Teraponidae 21 species: This group contains two of Australia’s most widespread species, spangled perch (Leiopotherapon unicolor) and banded grunters (Amniataba perciodes). However, most species are relatively restricted in distribution. In aquaria this group behaves the most like cichlids in respect that they can get quite aggressive. Grunters are usually best housed singly. Most grunters typically grow larger than 8 in. One species to look out for in the US once they start to be exported is the coal grunter, (Hephaestus carbo). It is a brilliant black and gold species whose color is most vivid when small. They are best obtained when they are less than 2 in, although be prepared for them to grow up to 1 ft after 5 years or so! Many grunters make attractive angling species because of their size and some make excellent eating, although others such as leathery grunter (Scortum hillii) do not (name says it all!). Most grunters make very tame family pets that are good for disposing of trash fish.

Gudgeons Eleotridae 28 species: Also known in many places as gobies (not within Oz though), however this term should only be applied to the family Gobiidae. Gudgeons are an incredibly interesting, colorful and entertaining group of fish that have almost completely been ignored by aquarists in Australia. They are known from most of Australia including southern areas. Some species, such as the purple spotted gudgeon (Mogurnda spp.), are available in the US and are very easily bred, although care needs to be taken that the females are not killed by males. Unfortunately, the spectacularly colored empire or carp gudgeon (Hypseleotris compressa), which is also available occasionally overseas, have fry which are 1/25th of an inch long which makes them particularly difficult to raise, (although not impossible). There is a spectacular diversity of gudgeons within New Guinea, in excess of 40 species are recorded including the incredibly colored peacock gudgeon, (Tateurndina ocellicauda). Little is known about the breeding behavior of many gudgeons because so few have been kept in aquaria. Many species have very small fry which are very challenging to raise. The fry of species such as purple spotted and peacock gudgeons are very easy to raise in a similar fashion to rainbows. Typically they are also relatively slow growing.

Gobies Gobiidae 17 species (plus many more brackish/marine species): Gobies worldwide have been ignored by fishkeepers. They are the most diverse family of fish with over 2000 species. Gobies are found throughout Australia, although very few species are truly freshwater. Gobies are a comical, fascinating, and clumsy group of fish which are a delight to watch. The family includes the desert goby (Chlamydogobius eremius), Australia’s equivalent of the pupfish (Cyprinodon). Several species of desert goby exist in desert springs, some of which are also endangered like the pupfish. Desert gobies can typically tolerate temperatures between 40 and 104 °F and salinities up to 60 ppm. Gobies are a very poorly known group of fishes, especially when it comes to their breeding behavior. The few Australian species that have been spawned have laid eggs in caves or a tube. Males usually guard the eggs until they hatch. If the fry are large they are usually easily raised similar to rainbows. Unfortunately many species have very small fry.

Pygmy perches Nannopercidae 6 species: Pygmy perches are a very friendly and attractive group of fish. While they rarely grow larger than 2 in they react very enthusiastically towards their owners. This and the last family is found throughout temperate Australia, as a result they require cooler conditions, preferably below 70 °F, although some will tolerate slightly higher temperatures. They are very rarely kept or bred in aquaria despite their great appeal and attractive coloration.

Galaxiids Galaxiidae 21 species: Galaxiids are considered to be a southern hemisphere branch of the trout family (Salmonidae). The two groups also share many ecological similarities. I have spent time watching galaxiids in small mountain streams and they even behave virtually the same as trout. Unfortunately, the introduction of trout to Australia has had a dramatic impact on some galaxiids. Several species are threatened with extinction because of trout predation. Most galaxiid species grow to 6in, although one genus Galaxiella, only grows to 1 1/2 to 2 in maximum. Galaxiids make incredible aquarium fish, they very active midwater swimmers which prefer a large cool tank. They are very aggressive feeders, it is quite entertaining to feed them some mosquitofish and watch them be devoured, (another introduced North American trash fish that has caused significant problems in Australia). Unfortunately, except for the Galaxiella, none have ever been breed in captivity as many species have a complicated life cycle which involves migration between fresh and salt water.

Unfortunately the most disappointing thing in dealing with Aussie natives is the lack of interest that local Aussie fishkeepers show in them. Very few species other than rainbowfish are kept, and even then it is only the best known rainbowfish species. Fortunately, in addition to the Rainbowfish Study Group, there is an Australian group who is also interested in Australian natives. This group is known as the Australian New Guinea Fishes Association (ANGFA), an organization that is devoted to spreading information on the keeping, collecting, and conservation of Australian fish. They publish a color journal 3 times a year with many excellent photographs of fish and habitats. I would thoroughly recommend this group to anyone who is serious about Aussie natives.

Reprinted from The Rainbowfish Times, Journal of The North American Rainbowfish Study Group. Volume 8(4): 9-14, 16. 1994.