The Enemy Within

by Daphne Layley

 ne of my favourite ways of passing a few hours used to be searching through a friendly dealer’s tanks of catfish, looking for any odd ones that might be different to the majority of the shipment.

On one of these forays I was confronted by a tank of juvenile Calophysus macropterus, a greyish, predatory Pimelodid with dark spots along its flanks. Closer inspection showed one specimen in there that didn’t have any spots. It was green/bronze metallic with a very long adipose fin and, most significantly, long and extremely flattened barbels. It was a Pinirampus pirinampu, a large Amazonian Pimelodid which was hardly ever imported for the aquatic trade.


Pinirampus pirinampu

Pinirampus pirinampu


It was as though all my birthdays had come at once and I couldn’t believe my luck as I took it home and installed it in a quarantine tank. It survived the mandatory three weeks, which I impose on all new purchases, and proved to have a healthy appetite for all the usual food-stuffs, worms, prawn, coleyfish etc. It grew rapidly lengthwise, from about 75 to 150mm. However, I always noticed that, although immediately after a meal it looked as though it had swallowed a plum, a few hours later its stomach was quite flat again. It didn’t seem to put on any actual body weight, only length, and I began to suspect something seriously amiss.

In desperation one day I decided to try soaking some food in Sterazin or a similar product, but the next morning, before I could put my plan into action, the fish looked rather poorly and was resting, quite uncharacteristically, up against the front glass in a head-up position, which meant that it’s undersides and belly where in full view. I could see something dark wiggling around inside and this ‘thing’ seemed to fill the whole body cavity,. An hour later the fish was dead.

Never having been one of these squeamish females, I cut my fish open and the worm that came out measured 125mm in length. It was about 0.5mm in width and reddish-brown in colour.

The worm died very quickly - obviously, its life-support system was no longer functioning.

Nobody would have guessed, after looking at my fish when I first got it, or even after several weeks, that it was playing host to an alien, and this causes me to wonder how often this happens with wild-caught fish and we don’t realise it at the time of purchase.

What I do know is that if I ever win the lottery and fulfil my life’s ambition, (which is to go on an expedition and see the Amazon and some of these catfish in their natural habitat), when the chef of the day offers me a catfish steak, I just might say thanks but no thanks.....

Daphne Layley, 2009

This article is an up-dated version of the original, first published in Magazine No. 69 of the Catfish Association of Great Britain, 1991.

Image credit: Nishant Kikani



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