| Phylum Chordata
> Subphylum Vertebrata > fishes |
Eeltail
catfishes
Family Plotosidae
updated
Aug 10
if you
learn only 3 things about them ...
They lack scales and are sometimes mistaken for eels or
snakes.
The 'whiskers' don't sting. They are used to find food
in murky waters.
They
have venomous spines. Don't touch them! |
|
Where
seen? These squirmy fishes that resemble eels are the only
catfishes commonly seen in coral reefs and intertidal areas. They
are sometimes abundant on many of our shores. Juveniles about 10cm
long or smaller can be seen close to mid-water mark, while larger
ones are often sighted hiding among seagrass or coral rubble in deeper
waters.
What are eeltail catfishes? Eeltail
catfishes belong to the Family Plotosidae. According to FishBase:
the family has 9 genera and 32 species. The marine species are found
in the Indo-West Pacific Ocean. Most of the members of this family
live in freshwater. Only a few are marine. 'Plotos' means 'to float'
in Greek.
Features: Juveniles from 5cm,
adults to about 30cm. The body is long and cylindrical, flattening
into an eel-like tail, i.e., the dorsal and anal fins are continuous
with the tail fin. To swim, the fish undulates in an eel- or snake-like
manner. Snout blunt with four pairs of 'whiskers’ (called barbels)
all around the mouth. One pair on the snout in front of the eyes,
one pair on each side of the mouth and two pairs below the mouth.
It lack scales and has a smooth slimy skin. It makes up for this 'nakedness'
with venomous spines on the dorsal fin and on each of the pectoral
fins. These tough spines can be locked upright, thus making an eeltail
catfish unpleasant for bigger fish to swallow.
Catfishes use their venomous spines to protect themselves against
predators, and not to catch prey. Their stings can be excruciating
and long-lasting. So please don't handle any catfishes.
Sometimes mistaken for sea
catfishes. Sea catfishes are seldom encountered on the intertidal
at low tide. Sea catfishes have barbels too but their tail fins are
forked and not eel-like as in the eeltail catfishes. Eeltail catfishes
are sometimes also mistaken for sea
snakes or eels (Family
Muraenidae). Here's more on how
to tell apart sea snakes, eels and eel-like animals.
What do they eat? Small ones eat
tiny animals and algae. Adult eel-tail catfishes are adapted for hunting
on the sea bottom in murky waters. Prey include crustaceans, molluscs,
worms and sometimes fishes. The barbels around the catfish's mouth
help find prey where visibility is poor. The barbels have taste buds
to help sense food. They don't use their barbels to sting. Catfish
also have a keen sense of hearing and a strong sense of smell. Like
other fishes, catfish smell with their 'noses' (nostril-like openings
on the snout).
Human uses: The Black eeltail
catfish is fished for food and sport in some places. Striped eeltail
catfishes are popular in the aquarium trade although they eat their
tankmates, and even one another, as they get bigger.
Status and threats: Our eeltail
catfishes are not listed among the threatened animals of Singapore.
But most striped eeltail catfishes sold in the aquarium trade are
wild caught as there have been no large scale successes in captive
breeding of these fishes. Like
other fish and creatures harvested from the wild, most die before
they can reach the retailers. Without professional care, most die
soon after they are sold. Those that do survive are unlikely to breed.
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'Whiskers' help it to find
food in murky waters.
Changi, Aug 05

Sentosa, Sep 04

Small ones may swim in tight groups.
Kusu Island, Jun 04

Great billed heron caught an eeltail catfish!
Chek Jawa, Jan 10
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| Like
other creatures of the intertidal zone, they are affected
by human activities such as reclamation and pollution. Over-collection
and over-fishing can also have an impact on local populations. |
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Family
Plotosidae recorded for Singapore
from
Wee Y.C. and Peter K. L. Ng. 1994. A First Look at Biodiversity
in Singapore.
in red are those listed among the threatened
animals of Singapore from Ng, P. K. L. & Y. C. Wee, 1994.
The Singapore Red Data Book: Threatened Plants and Animals of Singapore.
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Links
- Black
eeltail catfish (Plotosus canius) Tan, Leo W. H. &
Ng, Peter K. L., 1988, A
Guide to Seashore Life. The Singapore Science Centre,
Singapore. 160 pp.
- White-lipped
Eeltail Catfish (Paraplotosus albilabris), Black
Eeltail Catfish (Plotosus canius), Striped
Eeltail Catfish (Plotosus lineatus) Lim, Kelvin K.
P. & Jeffrey K. Y. Low, 1998. A
Guide to the Common Marine Fishes of Singapore. Singapore
Science Centre. 163 pp.
- Family
Plotosidae from FishBase:
Technical fact sheet on the order, including fact sheets.
- Family
Plotosidae on Coastal
Fishes of Indonesia: Field Guide to Lombok Island by Keiichi
Matsuura, Seishi Kimura and Teguh Peristiwady on the National
Science Museum, Tokyo website: factsheets with photos and descriptions
with details on similar families.
- Family
Plotosidae from Fishes
of Libong Island (West Coast of Southern Thailand) by Keiichi
Matsuura and Seishi Kimura (eds.) on the National Science Museum,
Tokyo website: factsheets with photos and descriptions with details
on similar families.
- Family
Plotosidae from Fishes
of Bitung (Northern Tip of Sulawesi Indonesia) by Seishi Kimura
and Keiichi Matsuura (eds.) factsheets with photos.
- Sting
of the cat: thousands of catfishes may be venomous on the
wild shores of singapore blog.
References
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