Pest Fish Identification Guide · PDF fileAn easy way to distinguish a pest fish from a native freshwater fish is by ... • Prevent accidental escapes—comply with aquaculture permit

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Pest fish of Queenslandidentification guide

Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

CS1054 11/11

© The State of Queensland, Department of Employment, Economic Development and Innovation, 2011.

Except as permitted by the Copyright Act 1968, no part of this work may in any form or by any electronic, mechanical, photocopying, recording, or any other means be reproduced, stored in a retrieval system or be broadcast or transmitted without the prior written permission of the Department of Employment, Economic Development and Innovation. The information contained herein is subject to change without notice. The copyright owner shall not be liable for technical or other errors or omissions contained herein. The reader/user accepts all risks and responsibility for losses, damages, costs and other consequences resulting directly or indirectly from using this information.

New South Wales Department of Primary Industries has granted full permission for use of the text and images included within this document.

Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Is it a pest fish?

An easy way to distinguish a pest fish from a native freshwater fish is by looking at the dorsal fin. Pest fish usually have a continuous dorsal fin, while native freshwater fish usually have a dent or gap separating the front of the dorsal fin from the rear.

ContentsAbout this guide 2

Pest fish and their impacts 2

What can you do? 3Recreational fishers 3Ornamental fish enthusiasts and backyard pond owners 3Fish farmers 3

Rules surrounding pest fish 4

Mozambique tilapia (Oreochromis mossambicus) 5

Spotted tilapia (Tilapia mariae) 7

Carp (Cyprinus carpio) 8

Gambusia (Gambusia holbrooki) 10

Goldfish (Carassius auratus) 11

Three-spot gourami (Trichogaster trichopterus) 12

Pearl cichlid (Geophagus brasiliensis) 13

Oriental weatherloach (Misgurnus anguillicaudatus) 14

Climbing perch (Anabas testudineus) 15

Redfin (Perca fluviatilis) 15

Fish features 17Pest fish 18Native fish 18Tail shapes 18

Glossary 19

2 Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

About this guideThis guide will help you identify pest fish that live in Queensland’s fresh waters. The guide explains how pest fish affect natural aquatic ecosystems and outlines what you should do if you capture a pest fish. The guide only includes pest fish that are currently or potentially posing significant threats to the natural freshwater environments in Queensland—it is not an exhaustive list of all pest fish found in Queensland.

The pest fish profiles contain general information about the species, their distinguishing features and their habitat preferences. The photographs and line drawings highlight the distinguishing features of the fish.

The process for reporting a pest fish sighting is outlined on page 3 and the contact details for reporting are repeated at the bottom of each page.

Pest fish and their impactsPest fish are species that are not native to an area and have potential negative social, economic or environmental impacts. Populations of pest fish have successfully established in many of Queensland’s local waterways and are a major threat to the high diversity of native freshwater fish in Queensland and New South Wales.

The presence of pest fish in natural waterways can have some serious impacts such as:

Habitat

• decreased water quality• increased water turbidity and siltation• increased nutrient loads.

Native fauna and flora

• introduction of diseases and parasites• decreased biomass and diversity of rooted water plants• reduced numbers and diversity of native aquatic fauna (through direct

competition for food or space, or predation)• decreased numbers and diversity of aquatic insects• altered food chains and other ecological processes• increased dominance of waterbodies by pest fish.

Economic and recreational

• increased pressure on recreationally significant species (e.g. through competition)• reduced environmental and conservation value of infested waterbodies• diminished recreational value of infested waterbodies• reduced value of recreational and/or commercial fisheries.

3Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

What can you do?Queensland Government relies on members of the public to report new pest fish incursions. Information about pest fish sightings is vital in managing their impacts.

• If you sight or catch a pest fish in Queensland, please report it by calling 13 25 23 or by emailing [email protected]. Please include as much information as possible including detailed information about the location (GPS coordinates, landmarks, roads, etc.), the type of waterbody, a description of the fish and, if possible, whether a photograph or frozen specimen of the fish was retained. Visit www.deedi.qld.gov.au for more details.

Recreational fishers• Don’t transfer pest fish between waterways—don’t use pest fish as bait.• Obtain a permit to stock fish. Buy fingerlings from a registered hatchery to

minimise the chance of contamination with undesirable species.• Don’t return pest fish to the water. If you catch a pest fish, kill it humanely and

dispose of it appropriately.• Prevent unwanted hitchhikers—check, clean and dry your boats and gear

between waterways.

Ornamental fish enthusiasts and backyard pond owners• Don’t dump fish—give unwanted aquarium fish to friends or a pet shop instead

of letting them go in the wild.• Prevent accidental escapes—screen outdoor ponds to prevent overflow during

heavy rains.• If possible, keep native fish instead of exotics—contact your local aquarium or

Fisheries Queensland on 13 25 23 for information on local native fish species.

Fish farmers• Prevent accidental escapes—comply with aquaculture permit conditions

designed to prevent the escape of fish (e.g. screened water outlets).• Don’t experiment with exotics—keep to the prescribed species list.

[email protected]

www.deedi.qld.gov.au

Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au4 Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Rules surrounding pest fishLaws exist for the possession or sale of some exotic fish species that are found in Queensland waterways. Legislation is constantly being updated. For the most current information on prohibited fish species visit www.deedi.qld.gov.au or call 13 25 23.

Some prohibited fish species legally require euthanasia by anyone who comes into possession of them. The most humane method for euthanasing a prohibited fish is by following the ethical euthanasia protocols recommended by the Australian and New Zealand Council for the Care of Animals in Research and Teaching (ANZCCART). The 2001 ANZCCART publication Euthanasia of animals used for scientific purposes states that the most appropriate method involves stunning the fish via a sharp blow to the back of the head just above the eyes. When applied correctly, this causes brain destruction—the fish’s gill covers should stop moving and its eyes should remain still. The dead fish should not be returned to the waterway and instead should be either buried well away from the water or disposed of in a rubbish bin.


Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au 5Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Mozambique tilapia (Oreochromis mossambicus)

Other names: Mozambique mouth-brooder.

General information: Mozambique tilapia were first introduced into Australia in the 1970s as ornamental fish and are now regarded as one of the greatest threats to Australia’s native biodiversity. Females carry juveniles and eggs in their mouths, and these can survive for a considerable time after the adult dies. Therefore, new incursions can occur when live or dead fish are released into a waterway.

Size: Up to 40 cm long.

Distinguishing features: These fish are generally deep-bodied with a thin profile. They are mostly dark grey or almost black but can be silver with 2–5 dark blotches or spots on the side. Breeding males can have red tips on their fins. Their caudal fin is truncate with rounded corners. Juveniles have a small black spot at the rear of the base of the dorsal fin and may have vertical banding on the body. The fish (especially males) have a long snout and pronounced lips/jaws. They have a single, continuous dorsal fin originating near the head and ending with an extended point. Their dorsal fin and anal fin are almost symmetrical.

Male Mozambique tilapia Female Mozambique tilapia

Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au6 Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Colourful adult male Junvenile Mozambique tilapia

Typical habitat: They can be found in a variety of habitats including reservoirs, lakes, ponds, rivers, creeks, drains, swamps and even tidal creeks and estuaries. They usually live in mud-bottomed, well-vegetated areas and are often seen in loose aggregation or small schools. They mainly inhabit slow-flowing rivers and streams and still-water habitats. The males build clusters of circular nests or pits in sandy or muddy substrate.

Mozambique tilapia nests Eggs in the mouth of a female

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Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au 7Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Spotted tilapia (Tilapia mariae)

Other names: Black mangrove cichlid, spotted mangrove cichlid.

General information: Spotted tilapia were first introduced into Australia as ornamental fish and are now regarded as one of the greatest threats to Australia’s native biodiversity.


Distinguishing features: These fish are generally deep-bodied with a thin profile. Their colour ranges from dark olive-green to light yellow and they have 8 or 9 dark bars or blotches on the sides (more evident in younger fish). Adults can have red margins on their fins and red blushing on their bodies. Their caudal fin is truncate with rounded corners. Juveniles have a small black spot at the rear of the base of the dorsal fin. Their single, continuous dorsal fin originates near the head and ends with an extended point.

Typical habitat: They can be found in both still and flowing waters and prefer rocky or muddy bottomed habitats in both non-tidal and estuarine waters.

Spotted tilapia Juvenile spotted tilapia

Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.auReport a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au8

Carp (Cyprinus carpio)

Common carp

Koi carp

Mirror carp

NSW

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9Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.auReport a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Other names: Common carp/European carp, koi carp, mirror carp.

General information: Three varieties of carp are present in Australian waters—common carp, koi carp and mirror carp (these are all the same species). Carp were originally imported into Australia as game fish and have since spread throughout many waterways, including the Murray-Darling Basin. It is illegal for carp to be used as ornamental fish in Queensland. Carp pose a major environmental threat, as they can rapidly outnumber native fish and greatly disturb aquatic environments through their destructive feeding habits.


Distinguishing features: These fish are medium-sized and have large, thick scales. They vary in colour but are usually olive-green, bronze or silvery-grey on the back, lightening to cream or silvery-yellow on the sides and the underside. Koi carp are often brightly coloured with dark blotches over the back. Their caudal fin is deeply forked. The fish have a moderately sized mouth with thick, fleshy lips and two pairs of barbels (whiskers) at the corners (see photograph, below left). Their single dorsal fin originates halfway down the body and has a stout, serrated spine at the front.

Typical habitat: They prefer warm, still rivers or lakes with silt bottoms and abundant aquatic vegetation. They are rarely found in clear, cool, swiftly flowing streams. They are tolerant of a wide range of environmental conditions and are able to survive extremely low levels of dissolved oxygen.

NSW

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Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au10

Gambusia (Gambusia holbrooki)

Other names: Mosquitofish, eastern gambusia, top minnow, plague minnow.

General information: Gambusia were first introduced into Australia from North America as a biological control for mosquitoes; however, this was unsuccessful. Instead, they have had a detrimental effect on native fish through competition for resources and their aggressive behaviour. They have a habit of nipping the fins of other fish, regardless of size differences. Also, they prey on the eggs and larvae of native fish and frogs.


Distinguishing features: These fish have a stout body with large, round scales. Females grow larger than males, have a deeper body and have a large, dark spot near the vent. Males are slimmer and have a slender, elongated anal fin. Their colour is usually olive-brown on the back, blue-grey on sides and white-silver on the underside. Some fish have small dots on the caudal fin, dorsal fin and body. Their caudal fin is truncate or rounded. Their head is flattened and mouth upturned. Their single dorsal fin is short, originates well back on the body and has soft rays.

Typical habitat: They are commonly found in lakes and still or slow-flowing streams. They are frequently around the edges or among freshwater plants. They generally inhabit warm, fresh and brackish waters at low elevations.

Adult male (below) and female eastern gambusia

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Male gambusia Female gambusia

Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au 11

Goldfish (Carassius auratus)

Other names: None.

General information: Goldfish are popular aquarium fish. They are native to eastern Asia and are now widely distributed in waterways throughout the southern half of Australia. They are often mistaken for carp; however, unlike carp, they lack barbels at each corner of their upper lip. Although goldfish do not seem to form large populations, they are still considered to have a negative impact on native freshwater fish. This is because they compete for food and habitat and have the potential to spread fish diseases and parasites.


Distinguishing features: These small, plump, deep-bodied fish are moderately compressed. They range in colour from bright yellow to black (usually depending on their habitat) and many have a mottled appearance. Their caudal fin is forked. They have a blunt head and a small, toothless, protrusible mouth with no barbels. Their single dorsal fin is long-based and originates halfway down the body. They have a single spine on the dorsal and anal fins.

Typical habitat: They are a subtropical, freshwater fish but prefer cooler waters. They are commonly found in streams, ponds and dams.

Gambusia (Gambusia holbrooki)

Other names: Mosquitofish, eastern gambusia, top minnow, plague minnow.

General information: Gambusia were first introduced into Australia from North America as a biological control for mosquitoes; however, this was unsuccessful. Instead, they have had a detrimental effect on native fish through competition for resources and their aggressive behaviour. They have a habit of nipping the fins of other fish, regardless of size differences. Also, they prey on the eggs and larvae of native fish and frogs.


Distinguishing features: These fish have a stout body with large, round scales. Females grow larger than males, have a deeper body and have a large, dark spot near the vent. Males are slimmer and have a slender, elongated anal fin. Their colour is usually olive-brown on the back, blue-grey on sides and white-silver on the underside. Some fish have small dots on the caudal fin, dorsal fin and body. Their caudal fin is truncate or rounded. Their head is flattened and mouth upturned. Their single dorsal fin is short, originates well back on the body and has soft rays.

Typical habitat: They are commonly found in lakes and still or slow-flowing streams. They are frequently around the edges or among freshwater plants. They generally inhabit warm, fresh and brackish waters at low elevations.

Adult male (below) and female eastern gambusia

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Three-spot gourami (Trichogaster trichopterus)

Other names: Blue gourami.

General information: Three-spot gourami are very hardy and highly invasive fish that can breathe air directly, allowing them to survive for long periods out of the water if kept moist. They are a tropical-subtropical fish native to South East Asia but have been introduced into many other areas, including north Queensland.

Size: Up to 20cm long.

Distinguishing features: These fish have an elongated, compressed body with a pair of pelvic fins in the form of long thin sensory filaments. They have a small, upturned mouth and a long-based anal fin. Their colour is usually a uniform blue with a pale olive tinge. They may also exhibit two dark spots—one at the base of the tail and the second in the centre of the midline of the body. (The common name suggests a third spot, which is the eye.) The fins contain small white spots.

Typical habitat: They are very tolerant of poor water quality and usually live in habitats that are heavily vegetated with shallow, sluggish or standing water. This includes waters such as marshes, swamps, canals, rivers and lakes.

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Pearl cichlid (Geophagus brasiliensis)

Other names: Pearl eartheater.

General information: Pearl cichlids were introduced into Australia for ornamental purposes. They are aggressive, attractively coloured freshwater fish native to South America. They can potentially become a significant pest, because of their size, hardiness and aggressive behaviour. Feral populations of this species are in several areas near the Tweed River in New South Wales and in parts of Western Australia.


Distinguishing features: These fish are higher bodied and laterally compressed. Their main body colour can range from pale light brown to greyish-green or dark blue or purple; they are lighter on the underside. They are covered with blue-white pearly flecks and often have a single dark spot on the side of the body. Smaller fish are usually plain brown. Their fins are either totally red or have red or black margins. Their caudal fin is truncate with rounded corners. The fish have a rounded forehead and small, pointed mouth. Adult males develop a slight hump on the head. Their single, continuous dorsal fin originates near the head and ends with an extended point. The dorsal fin and anal fin are almost symmetrical.

Typical habitat: They are very hardy and will tolerate most environments, including sea water.

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Oriental weatherloach (Misgurnus anguillicaudatus)

Other names: Japanese weatherloach, Chinese weatherfish, weatherfish.

General information: Oriental weatherloaches are native to Europe and Asia but have been introduced into Australia as ornamental fish. Individuals exist in natural waterways through the release of aquarium fish and through escapes from ornamental ponds.


Distinguishing features: These fish are small, elongated and cylindrical with small eyes. Females are more solidly built than males and have rounded pectoral fins; males’ fins are more triangular or square-cut. Males also have a long, thick pectoral ray. The fish are usually a mottled yellow-brown with black spots and a pale underside. They have a prominent black spot at the base of the caudal fin, which is rounded. Their mouth is small, down-turned and surrounded by five pairs of barbels. Their single, short dorsal fin is further down the body. The fish are covered in mucus, making them very slippery.

Typical habitat: These benthic fish are commonly found in slow-flowing or still water with sand, mud or detritus substrates into which they can burrow. They can survive in habitats ranging from degraded urban and rural streams and ponds to relatively pristine headwater streams.

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Climbing perch (Anabas testudineus)

Other names: Climbing gourami, walking fish.

General information: Climbing perch are native to Asia, where they are commercially fished as an important food source. They have an accessory air-breathing organ, which allows them to survive out of the water for several days in moist conditions. This gives them the ability to travel across land on their pectoral fins. They have a highly developed predatory nature and, in times of drought, are able to bury themselves in the mud to survive. Although there are currently few reported cases of climbing perch in the wild in Australia, the species’ dispersal and survival ability presents a high risk to Queensland’s aquatic environment. North Queensland is especially at risk, as there have been confirmed reports of climbing perch in the Torres Strait Islands.


Distinguishing features: These fish have elongated bodies and various strong spines on the posterior edge of their gill covers. Females have a larger girth than males, and males have more of a knife-edged anal fin. They are a ‘muddy’ pale brown-orange to dark greenish-brown with occasional dark blotches over their body. Males tend to be darker than females. Younger individuals have a dark spot on their caudal peduncle. Their caudal fin is truncate with rounded corners. Their single dorsal fin originates near the head and extends the length of the body. Their dorsal and anal fins reach backwards to the beginning of the caudal fin.

Typical habitat: They are a tropical fish that inhabit fresh and brackish waters throughout the world. They are most often found in canals, lakes, ponds and swamps. They can tolerate extremely unfavourable water conditions such as low oxygen and extreme temperatures.

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Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.auReport a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au16

Redfin (Perca fluviatilis)

Other names: Redfin perch, English perch.

General information: Redfin are native to Europe and were introduced into Australia in the 1860s for angling; these fish were popular for their fighting qualities and taste in the United Kingdom. Although there are currently no reports of redfin in the wild in Queensland, they are a significant pest in New South Wales and there is a high risk of them being spread into Queensland. They are voracious predators of other fish and invertebrates and can destroy recreational fisheries in enclosed waters by building up large numbers of stunted fish and eliminating other species. Redfin can devastate native fish populations by carrying the viral disease epizootic haematopoietic necrosis (EHN). A number of native species, including silver perch, Murray cod, mountain galaxias and particularly Macquarie perch, are highly susceptible to EHN.


Distinguishing features: These deep-bodied fish have a slightly forked caudal fin. Their body colour fades from olive-green on the back to greenish or silvery on the sides and whitish on the belly. They have bright reddish-orange pelvic, caudal and anal fins. Also, they have a pattern of five or more broad black vertical bands across the back, tapering on the sides (more prominent in younger fish). Unlike most introduced freshwater species, they have two distinctly separate dorsal fins, the first with 12–17 strong spines and a distinct black blotch at the rear.

Typical habitat: They live in a variety of habitats, but prefer still or slow-flowing waters such as lakes, dams, billabongs, swamps and slower moving streams and rivers. They prefer areas with good shelter such as snags (submerged deadwood and trees), vegetation or rocks, but have also been caught in open water.

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17Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.auReport a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Fish featuresThe main features used to identify a fish species are shown in the following diagrams:

stripes

bar

blotches

saddleblotch

bandspotsdotsmaxillary

streak

dorsal fincaudal peduncle

length

caudal fin

anal finanus

lateral line

body depth

total length

pectoral fin

operculum

pelvic fin

head length

18 Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Tail shapesThe different tail shapes of fish are shown in the following diagrams:

Pest fish versus native fishAn easy way to distinguish a pest fish from a native freshwater fish is by looking at the dorsal fin. Pest fish usually have a continuous dorsal fin, while native freshwater fish usually have a dent or gap separating the front of the dorsal fin from the rear.

rounded convex emarginate

truncate truncate with rounded corners

lunate forked

concave

NSW

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Pest fish Native fish

Barramundi

Australian bass

Mozambique tilapia

Carp

19Report a pest fish! Call 13 25 23, email [email protected] or visit www.deedi.qld.gov.au

Glossarybarbel a slender, tentacle-like sensory structure on the head;

a ‘whisker’

base the part of a projection (e.g. a fin) connected to the body

blotch an enlarged area or patch that is different in colour from adjacent areas

brackish slightly salty; a mixture of sea water and fresh water

caudal pertaining to the tail or posterior part of the body

common name the informal name for an animal

dorsal relating to the upper part or surface

lateral relating to the sides

margin the edge or rim

mottled having the appearance of uneven spots or blotches of different shades or colours

new incursion the reporting or sighting of a pest fish species in an area where it has not previously been recorded

pectoral relating to the chest or thorax

peduncle the part of the body posterior to the anus and to which the caudal fin attaches

posterior behind or at the back of

ray a stiff, bony spine in the fin of a fish

scientific name the formal organism name consisting of the genus and the species

snout the part of the head in front of the eyes

spine a sharp, protruding point; also, the backbone or vertebral column

symmetrical showing symmetry; having similarity in size, shape and relative position about a midline

Report a pest fish!Call 13 25 23 email [email protected] or visit www.deedi.qld.gov.au

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Documents

Pest Fish Identification Guide · PDF fileAn easy way to distinguish a pest fish from a native freshwater fish is by ... • Prevent accidental escapes—comply with aquaculture permit