n the United States, two species of Ictalurid catfish,
the Channel Catfish and the blue Catfish, have been hybridized
for some time. Commercial Catfish production for food
is big business out there and the resultant hybrids have
a growth rate which is up to four times faster than that
of either of the parent fish (hybrid vigour). They grow
faster and they reach saleable (and edible) size quicker
– the industry is huge and is worth millions of
dollars every year.
There are similar scenarios in
various other parts of the world involving the mass production
of food fish for human consumption. Clarius species are
hybridized in the Far East in massive commercial establishments,
and so it goes on. The whys and wherefores of such things
are not what this article is about.
My gripe is about producing hybridized
fish for the ornamental aquarium trade. As if the artificial
production of Flowerhorn and Parrot cichlids wasn’t
bad enough in the 1990’s, the floodgates seem to
have opened and for several years now we have had various
catfish hybrids, mostly within the Pimelodidae family,
namely Amazonian Redtail Catfish (Phractocephalus)
crossed with Tiger Shovelnose Catfish (Pseudoplatystoma)
and to a slightly lesser extent we also have Phractocephalus
crossed with another Pimelodid, Perrunichthys perruno.
There are others, too numerous to mention.
|
The
above image, as far as we know, is a hybrid cross
between Phractocephalus hemioliopterus (Red
Tail Cat) and a Pseudoplatystoma species,
possibly P.corruscans, but more than likely
P.tigrinum. |
More recently, the local fish shops
have been ‘flooded’ with Synodontis
hybrids and these are so many and so varied that it’s
sometimes difficult to distinguish between a true species
and a cross, even to the experienced eye.
|
The
above Synodontis sp. is sold in the aquatic
outlets as S. pardalis but could be a
S. occelifer/S eupterus cross although
a S. nigrita influence may be a possibility
too.
|
The ultimate disgrace has to be
the artificial cross between a Redtail Catfish and one
of the largest members of a totally different and unrelated
family, Pangasiidae – namely Pangasius sanitwongsei
- a Paroon Shark, no less. I believe that this is absolutely
disgusting – both these species grow huge –
how large might such a hybrid grow – with the benefit
of ‘hybrid vigour’ it could possibly reach
a larger size than either parent!!! What will the owners
do when it gets to four feet (120cm) long and it’s
still growing fast? Maybe we already know the answer to
that one.....
All these species are magnificent
fish in their own right, (even though some are too large
for the average hobbyist). What motivates people to think
that they can improve on nature? – they never will!
It has to be for purely financial reasons although they
may disguise it in the name of advancing scientific knowledge.
What next I wonder – are
they working on crossing an Angelfish with a Guppy even
as I write?
If someone crossed a cat with a
dog, or a horse with a cow, or a parrot with an emu, all
the animal welfare societies and animal rights activists
throughout the world would be up in arms and there would
be international condemnation. However, because fish aren’t
warm and furry or cuddly, it apparently doesn’t
matter. What would be the natural progression after that
– humans crossed with Gorillas?
Where will it all end?
We should refuse to buy these
fish, and we should make our feelings known to the shops
that sell them!
Image Credits:
Top: Chris Ralph.
Bottom:
Allan James @
