Aquarium (and Pond) Answers: Black Ghost Knife Fish, Electric Eel electric shock?

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Friday, December 15, 2006

Black Ghost Knife Fish, Electric Eel electric shock?

Can a Black Ghost Fish Produce an Electric Shock?>
Updated 7/13/10

QUESTION:
Can black ghost knife fish give an electric shock?

ANSWER:
No, but black knife fish do produce an electric current.
Black Ghost Knives have a small electrode sensor near their nose to sense and smell since they have almost no use of their eyes. Black Ghost Knife fish are nocturnal and are always found looking for food at night. The sensor emits a small electric current in the water which is not felt by any other fish and will not cause any harm.

The reason the current is not felt, is that knife fish produce volts, but few amps. Even their cousin, the electric eel is capable of large voltage output, but low amps (usually around 1 amp), which is why they are not very dangerous to humans, although they can stun smaller prey.

Further Electric Eel Information

Here is some data on Electrophorus electricus, the electric eel.

*Maximum recorded voltage: 550 volts (at 1 amp). This was recorded for a 2 m long fish (the size of the fish is related to the size of the electrical discharge).

*Length of pulses: a few milliseconds, so it's not long enough to heat up the filament on a standard incandescent light bulb.

*These discharges are usually not used to kill, but to either stun prey or convince threatening organisms to go elsewhere.

*While powerful enough to knock a person down, it's extremely unlikely electric eels could kill a person.

*From: Paxton, J. R. and Eschmeyer, W. N. (Eds.). 1994. The Encyclopedia of Fishes, p. 112

For those who read this and think about all the Yahoo Answers posts and other inaccurate web articles then scratch their heads thinking, “wait, this guy is stating the opposite of what most others are stating”, well you need to deeper past all these anecdotal posts from those with little understanding of the physics of electricity that come up on Google. One such comment is “the electric eel can discharge 6 times the electric charge (power) of household current”. This is incorrect when you factor in the fact that normal household current is at 10-15 amps vs. the Electric Eel at 1 amp. For example an electric heater that uses 10 amps @ 120 volts = 1200 Watts. An electric eel at 1 amp @ 600 volts is 600 watts; as well the Electric Eel only discharges for a very short periods at this voltage (often only milliseconds).

Please see this educated web page about this subject from a professor of physics:
Electric Eel at the Aquarium

This article shows the irregularity of DC voltage as well the video in this article only show low wattage Christmas lights, not a heater or other device that would use the amount of electricity to seriously harm a human:
How Much Electricity Can an Electric Eel Produce

A Few Facts:

*Origin; Amazon and Paraguay Rivers
*Max size; 16- 20 inches
*Recommended Aquarium Size; 50 gallons (larger is even better)
*Temperature; 72- 80F
*Water Conditions; Prefers water near 7.0, but like all FW fish still needs electrolytes and calcium. VERY sensitive to poor water conditions. I recommend reading these two articles:
“Aquarium Disease Prevention”
“Why Calcium and Electrolytes are important”
*Foods; Prefers live foods (bloodworms, black worms, brine shrimp)
*Tank furnishings; Ghost Knife fish need a place to hide, a clear plastic tube provides this and allows you to still see your pet (Lee’s aquarium products makes one)
*Genus: Apteronotus
*Species: albifrons

*Related fish include the Elephant Nose Fish (Gnathonemus petersii) which have similar requirements and reach a size of approximately 10" (although from the Niger River area of West Africa)

For up to date aquarium info (especially Redox and dispelling UV myths), please visit this site:
AQUARIUM AND POND INFORMATION;
Well researched and up to date aquarium and pond answers, help, and links. Based on 30+ years of professional aquarium maintenance experience.

For an experienced aquatics forum:
Everything Aquatic

# posted by Carl : 6:00 PM

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Friday, December 15, 2006

Black Ghost Knife Fish, Electric Eel electric shock?

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