Perca
Perca (Percichthys trucha) is Patagonia's only native freshwater predator worth targeting on a fly rod.
While introduced trout dominate the region's fishing culture, perca share the same spring creeks, lakes, and Andean rivers — and they're a genuine piece of the ecosystem that existed before the Europeans arrived with their trout eggs.
Found across Patagonia and Cuyo, they're a bonus catch for most visiting anglers and a point of pride for those who seek them out specifically.
Scientific Name: Percichthys trucha
Also known as Perca criolla, trucha criolla, trucha criolla bocachica, perca de boca chica, Creole Perch, lipüng (Mapuche)
- Elongated, oblong body with a small head and notably small mouth — the "bocachica" (small mouth) name is a reliable field ID marker.
- Back runs olive to blue-gray or slate; belly is pale violet; gill plate is reddish with dark brown spots on the scales.
- Tail fin is yellow-violet with dark spotting; dorsal fin has a distinct notch separating the spiny front section from the soft rear portion.
- Typical fish run smaller than the trout sharing their water; maximum age is around 10 years, so large specimens are genuinely old fish.
What to know
Habitat Distribution
- Native to freshwater systems of Patagonia and Cuyo in Argentina — one of the few fish in these watersheds that was here before introduced trout arrived.
- Occupies rivers, streams, lakes, and spring creeks across the Andean foothills and steppe; documented in both the Patagonia and Cuyo regions.
- Found alongside introduced brown and rainbow trout in waters like Arroyo Pescado and the rivers of the Esquel and Trevelin region.
- Can tolerate some salinity, but the fishery is entirely freshwater in Argentina.
Key Locations
- Arroyo Pescado (Chubut province) — one of Patagonia's most famous spring creeks; perca share the water with wild brown and rainbow trout.
- Esquel and Trevelin region (Chubut) — rivers and spring creeks of the Andean foothills where perca are regularly encountered alongside introduced trout.
- Los Alerces National Park area — Andean lakes and rivers within the park hold native perca populations.
Specific Spots
- Spring creek sections with slower currents and cruising lanes — perca patrol these the same way trout do, moving in search of food rather than holding tight to one lie.
- Narrower, faster sections of spring creeks where current concentrates food; the lower, technical stretches of streams like Arroyo Pescado hold fish that are harder to approach.
- Lake margins and river edges with structure — the small mouth limits what they can eat, so they tend to work shallower water where smaller prey is accessible.
Perca FAQ
Answers from onWater's species guide.
What are the best lures and bait for Perca?
Small spinners (sizes 0–2) and compact spoons are the most reliable conventional hardware, keep the profile small to match the perca's limited mouth size. Small soft plastics and micro jigs can work in slower water; natural bait such as worms is used by local anglers fishing from shore.
What flies work for Perca?
Nymphs are the foundation: Pheasant Tail Nymphs (imitating mayfly nymphs) and Hare's Ear Nymphs (imitating a broad range of aquatic invertebrates) in sizes 14–18 dead-drifted, allowed to drift naturally with the current, through feeding lanes produce consistently.
When is the best time to fish for Perca?
The Argentine trout season, roughly November through April, covers the main fishing window for perca in Patagonia, aligning with the Southern Hemisphere spring and summer. Spring (November–December) and autumn (March–April) tend to produce the most active surface feeding as water temperatures moderate.
How do you catch Perca?
Most anglers encounter perca while fishing for trout on Patagonian spring creeks and rivers, using the same nymph and dry fly presentations.
What do Perca eat?
The small mouth is the key detail: perca eat smaller prey than the trout around them, aquatic invertebrates, small crustaceans, and juvenile fish that fit their bite. Nymph patterns like a Pheasant Tail (imitating mayfly nymphs) or a Hare's Ear (imitating a range of aquatic invertebrates) are reliable starting points.
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