Fishes - Page V2

	A CPIE Notebook Project – Keys to Aquatic Biota of Hawai‘i		Page V2

	Key to Freshwater Fishes of Hawai‘i
	FISHES Superclass Osteichthyes Fishes are the best adapted of all the vertebrates to the aquatic realm. Most of our fishes—in terms of number of species and number of individuals encountered in most lowland streams—are non-native. With a few exceptions, these freshwater animals are fairly easy to distinguish from one another, especially if captured and placed in an aquarium (for example, a small plastic one in the field) for observation. A useful description of fish form and anatomy related to movement and types & terminology of fins (see Fig. V2-1. Other sites with useful diagrams of fish external anatomy include Wikipedia and Badmans Tropical Fish. See CPIE for a list of fresh and brackish water fishes encountered in Hawaiian fresh and brackish waters or search the USGS NAS site for non-native species [ignore confusing "native" designation at this site; all fishes shown are exotic).

	Figure V2-1. Fish fin names (after Exploring Nature)	Figure V2-2. Pelvic fin positions

[FISHES]
	[NOTE THREE CHOICES HERE]
33a	(26)	Pelvic fins near anus: abdominal in position (Fig. V2-2, left)	[34]
33b		Pelvic fins very near, under, or in front of pectoral fins: thoracic in position (Fig. V2-1 & Fig. V2-2, right)	[41]
33c		Without pelvic or pectoral fins; all other fins greatly reduced or not evident. Body eel-like, to 70 cm (24 in) long, tapering at hind end to a point. { Found in wetlands like Kawainui Marsh on windward O‘ahu, burrowing in bottom mud. Taunagi or rice paddy eel. Rare~ Family Synbranchidae Monopterus albus (Zuiew)
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	[NOTE THREE CHOICES HERE]
34a	(33)	Two widely separated dorsal fins, the first with four spines, second with soft rays. Pectoral fins set high on body (Fig. V2-2, left). Marine and brackish water, in estuaries and lagoons. Mullets ~ Family Mugilidae	40]
34b		Adipose fin (a small, fleshy dorsal lobe without rays, but may be supported by a spine) present behind larger dorsal fin, the latter with or without spines	[36]
34c		With a single median, dorsal fin; no separate spiny dorsal in front of a soft dorsal and no adipose fin	[43]
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36a	(34)	Mouth terminal and lacking barbels (fleshy appendages). Scales present	[37]
36b		Mouth>, if terminal or sub-terminal, then having conspicuous barbels; OR mouth ventral (directed downward, under nose) and with or without papillae or barbels. Body with or without scales. { Catfishes	[39]
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37a	(36)	Fish long, height about 1/5 of total length. Teeth small	[38]
37b		Fish length only about three times height. Dark black with flesh-colored to rose under chin and on abdomen. Mouth with very large, conical teeth within. Reservoirs. Pacu ~ Family CHARACIDAE Colossoma macropomum Cuvier
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38a	(37)	Strikingly colored with 5 to 10 black bands on yellowish or orange, bars increasing in number with age. Dorsal fin with 2 spines. Banded leporinus ~ Family CHARACIDAE Leporinus fasciatus (Bloch)
38b		Body silvery, with black spots and rosy hue along midline. Dorsal fin without spines. Stocked in a few high elevation streams. Rainbow trout ~ Family SALMONIDAE Oncorhyncus mykiss Walbaum
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39a	(36)	Mouth terminal, with long barbels (4 pair) on snout. Body without scales or armor plates, but with serrated pectoral spines. Introduced in some reservoirs. Channel catfish ~ Family Ictaluridae Ictaluris punctatus (Rafinesque)
39b		Mouth subterminal or ventral; with or without surrounding papillae or barbels. With scales or armoring	[40]
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40a	(39)	Mouth ventral (directed downward) and surrounded by barbels, but not sucker-like. Body behind head almost triangular in cross-section. Sides armored with two series of overlapping plates; these plates without prickled surfaces. In very few streams. Smooth armored catfish ~ Family Callichthyidae Corydoras aeneus (Gill)
40b		Mouth ventral and sucker-like, with thickened lips. Without barbels, but may have papillae around snout. Body depressed, armored with rough plates, these coated with fine prickles. Very abundant in some urban streams. Spiny armored catfish ~ Family Loricariidae	[41]
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41a	(33)	Nostrils (nares) with a single opening on each side. Dorsal fin extending most the length of the body, from above operculum to caudal peduncle and having at least 14 spines in addition to many rays ~ Family CICHLIDAE	[80]
41b		Nostrils with two openings on each side. Dorsal fin usually much shorter, but always with 10 or fewer spines (Note: the full dorsal fin may have few spines but many soft rays which are flexible, segmented, and branching)	[42]
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42a	(41)	Body long, round or depressed (flattened top to bottom) in cross-section. Front dorsal fin with 6, usually filamentous (thin) spines. Tail fin rounded. Generally bottom-dwelling fishes	[67]
42b		Body compressed (flattened side to side). Dorsal fin with 4 to 10 stiff spines. Tail (caudal) fin truncate to forked. Generally mid-water fishes	[72]
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43a	(34)	Body narrow-elongate with mouth produced forward as a narrow beak; about 1/4 of total length of fish forward of eye. Dorsal and anal fins about equal in size and shape, located far back from small pelvic fins. Wahiawa Reservoir. Stickfish, needlefish, roundtail garfish ~ Family BELONIDAE Xenentodon cancila (Collette)
43b		Mouth not produced forward as a beak; much less than 1/4 of total length found forward of the eye	[44]
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44a	(43)	Body elongate, maximum height less than 1/4 of total length. Mouth terminal or ventral, surrounded by pairs of fleshy appendages (barbels)	[45]
44b		Body not particularly elongate, or at least maximum height greater than 1/4 total length. Mouth terminal or dorsal or ventral; barbels present or absent	[46]
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45a	(44)	Body narrow-elongate (a loach), almost eel-like, to 10-15 cm (4-5 in). Mouth ventral and surrounded by pairs of short barbels. Widespread in freshwater streams. Dojo or weatherfish ~ Family COBITIDAE Misgurnus anguillicaudatus (Cantor)
45b		Body not loach-like, but elongate, Mouth ventral and surrounded by four pairs of long barbels. Widespread in freshwater streams, but secretive; in deeper pools or in mud burrow. Puntat or Chinese catfish ~ Family CLARIIDAE Clarius fuscus
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46a	(44)	Lower jaw protruding and square viewed from above; mouth directed upwards and without barbels. Anal fin of males modified as an intromittent organ (long and narrow) located close to pelvic fins. Topminnows or toothed carps ~ Family POECILIIDAE	[47]
46b		Lower jaw not protruding: mouth either terminal or ventral (directed downwards). Anal fin normal in both sexes and distant from pelvic fins. Carps and minnows ~ Family CYPRINIDAE	[55]


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