A Fish With a Past, The Reed Fish by G.H.Jennings

First reproduced in PetFish Monthly

A Fish With a Past
THE REED FISH
(Erpetoichthys calabaricus)

By G. H. Jennings
Gerald is a Director of the Calypso Group www.calypso.org.uk, and webmaster of IFOCAS www.ifocas.fsworld.co.uk
Aquarticles

REED fishes, together with another genus of fishes, the polypterids, comprise a family of archaic origin and have extremely unusual features. These fishes, which are in the sub-Class Brachyopterygii, are some of the most ancient surviving relatives of a type long since extinct.

wpe2.jpg (82417 bytes) They were previously named Calamoichthys calabaricus, but since first publication of this article they have been re-named to Erpetoichthys calabaricus.

All these fishes are confined in habitat to tropical Africa, and both have certain very unusual and unique anatomical features which are worth mentioning.

They have retained certain characteristics of their ancestors not found in most modern fishes. A swim bladder is present but it is divided into two sections, a small left and a larger right section, and both of these sections lie in a position similar to the lungs of higher vertebrates, and indeed it is used as an accessory breathing organ. In fact, if they are not allowed access to an air supply they will drown, although they still have fully operational gills.

In their natural habitat they rest by day concealed under rocks and vegetation at the bottoms of the rivers and streams, waking at night and emerging from the water to hunt and capture their food on land and in shallow water, in a similar manner to amphibians, eating worms, small newts, and smaller fishes.

Of their breeding and manner of reproduction very little is known and no information on the actual breeding procedure is available, although it has been found that at certain times of the year the anal fins of the males thicken, swell, and become folded, in a similar manner to the livebearing tooth-carps. For this reason several authorities including eminent American aquarists are inclined to the idea that these fishes may indeed be livebearers.

As far as can be ascertained from the limited information available they are readily adaptable to aquarium life and can be kept with a reasonable degree of success. One point, however, which arises at this stage is that when confined they must have access to the surface and a hiding place in the tank, such as rockwork formed into caves etc. They are extremely tolerant as far as water conditions are concerned and in their native continent they abound in waters between 72 and 83F (22-28C). They eat a wide range of large live foods, although their growth rate is quite slow. For identification, ray counts and lateral line counts show: dorsal fins 7-13 rays, anal 9-14 rays; lateral line scale counts 6 to 17. Size up to 30 inches. It has been suggested by certain authorities that the number of rays in the anal fin is an indication of the sex of the individual.

The first reed fish I obtained was from one of the large local pet stores, and at the time of purchase I was informed by the manageress (I now realise rather kindly) that they were a fish very adept in the art of escapology, and that she had lost quite a number of specimens herself. After coaxing my new purchase into a large polythene bag and transporting it home, I checked the temperature of the tank, and released him into his new home, a 30 in. by 12 in. by 15 in. aquarium heavily planted with Aponogeton, Sagittaria and spatterdocks.

Upon release into the tank he decided to seek cover amongst the rockwork and pushed and thrashed a large cavity underneath the rocks, not to the advantage of the plant life, as while doing this his long body uprooted most of the plants. I realised after reading some literature on the fish that the answer was to give him a convenient shelter of his own, and he was duly provided with a large sheet of cork bark shaped so as to enable him to utilise the rather large cavity underneath. This was weighted down by placing the heaviest rock available over the bark. He immediately grasped the intention of this addition that gave him a ready made home and moved in shortly afterwards.

During the first couple of weeks I could persuade him to eat nothing; tubifex, daphnia, even garden worms and guppies - all were refused. I was beginning to think that here was another fish just a little out of the ordinary that was going to prove to be a difficult proposition, until it eventually dawned on me why he had refused food and yet remained reasonably well built. When introduced into the tank he was not quite alone; among several Corydoras and a Gyrinocheilus there were about a half dozen bumble-bee gobies in the tank, but now there were no bees to be seen. An expensive fish indeed!

After about two weeks I purchased another reed fish, one I thought to be a female to the supposed male I already had. This one was slightly larger than the original one, thicker in body and generally duller in colour. This one was introduced into the tank with great anxiety as I was none too sure of the compatibility of the two, but all this seemed unnecessary when they met, as the original one, far from disliking the newcomer, seemed completely and totally to ignore it.

Then, owing to an expansion in the number of tanks I had, I moved all the fishes into a larger fish room indoors, which had been furnished especially for a new range of aquaria and stands. At this time the reed fish were moved from their existing 30 in. by 12 in. by 15 in. tank into a new slightly larger one, 36 in. by 15 in. by 15 in. high. The change of house did not seem to affect them in any way, and they soon settled down in their new surroundings, and things ran very smoothly in their tank for about ten days.

On the tenth day in their new tank I was checking to see that all was well but could only see one reed fish there. After turning over all the likely hiding places, and stirring up the gravel, I arrived at the conclusion that one had at last taken a dislike to the other. However, after crossing to the other side of the room to check the other tanks, I noticed the tail end of the missing reed fish behind one of the stands on the floor, and when I pulled it out found that it was completely dried up. It had obviously found a minute gap in the cover glasses of its tank and escaped in that fashion. Since then I have been unable to find any more of these fishes for sale, though for the last year the one remaining one has put up with a wide range of conditions, and eats anything and everything. My ambition now is to obtain some more.