Longtail knifefish
📖 Overview
Occurs in swamps, creeks, and river with lentic waters. Preys on small invertebrates, particularly the larvae of aquatic insects . Breeds before the start of the rainy season or during the rainy season, with a fecundity count of 6473 eggs . Males persistently defend their territory and apparently make electric signals (by increased electric organ discharge (EOD) rates and interruptions thereof) to females passing by to draw in a spawning partner . Mature females' EODs are of higher frequencies than mature males . Plasma androgens modulate the EOD frequency during the breeding season . Embryos hatch on day 4; larvae begin to feed on day 11. The electric organ and electroreceptors are both present in the larva at the time of first exogenous feeding . Seems to reach sexual maturity at 1 year of age, based on breeding experiments .
🔬 Taxonomy
🐟 Physical Description
Anal soft rays: 195 - 300. : elongated.
🌀 Behaviour
Behavioural data for Longtail knifefish is currently being reviewed.
🦐 Diet
Diet information for Longtail knifefish is currently being compiled.
🥚 Reproduction
Eggs of 3 mm diameter are deposited among plants. Larvae hatch after 4 days and start feeding after 11 days.
🌍 Habitat & Distribution
Freshwater; benthopelagic; pH range: 6.0 - 6.5; dH range: 4 - 15. Tropical; 22°C - 28°C
🌿 Ecology
day 11
📐 Morphometrics
🌡️ Water Parameters & Tolerance
🛡️ Conservation Assessment
📊 Population Risk & Fisheries
🍽️ Edibility & Flavour
"Longtail knifefish is an edible species."
- Clear, bright eyes — cloudy eyes indicate age
- Firm flesh that springs back when pressed
- Fresh ocean smell, never strong or ammonia-like
- Bright red or pink gills, not grey or brown
- Shiny, moist skin with scales tightly attached
- Cloudy or sunken eyes
- Strong fishy or ammonia odour
- Soft, mushy flesh that doesn't spring back
- Discoloured or dry flesh
⚡ Nutrition
Detailed nutritional data for Longtail knifefish is currently being compiled from USDA FoodData Central.
🔬 Mercury Safety
Mercury data for Longtail knifefish has not yet been assigned. Please consult FDA/EPA guidance for general seafood safety advice.
🌿 Sustainability
🌐 Names & Taxonomy
| Language | Common Names |
|---|---|
| 🇬🇧English | Longtail knifefish |
| 🌍CES | dlouhoocaska obecná |
| 🇫🇷French | Poisson-couteau |
| 🇵🇹Portuguese | Sarapú |
| 🇪🇸Spanish | Morena Cuchilla |
Scientific Synonyms
| Scientific Name | Author | Year | Status |
|---|---|---|---|
| Carapus sanguinolentus | Castelnau | 1855 | Heterotypic |
| Gymnotus macrurus | Bloch & Schneider | 1801 | Synonym |
| Hildatia brasiliensis | Fernández-Yépez | 1968 | Synonym |
| Sternopygus marcgravii | Reinhardt | 1852 | Synonym |
🔍 Similar Species
🗺️ Global Occurrence Map
Occurrence records from the Global Biodiversity Information Facility (GBIF) - 204 records indexed .
👥 Community & Contribute
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