Kindly taking time off from answering catfish queries for Practical Fishkeeping Magazine and writing a book on Pufferfish, Chris Ralph introduces this month's featured catfish. As a devoted catfish fanatic for a number of years (probably more than he cares to remember) Chris has chosen to write this month about one of his all time favourites.

The Mother of Snails Catfish is not very commonly seen, although if you have kept one of these Doradids, then it is one that you will not forget in a hurry - due to the size to which it can grow. For this reason I have ended up with a small collection of these fish (ten at the last count!), all rescued from aquarists who can no longer accommodate them. I personally would not recommend that they be kept in any aquarium which is under 72" x 24" x 24", and, really, even this sized aquarium will be eventually outgrown. My collection is housed in a 12' x 48" x 36" tropical pond, which just about allows them space to swim and turn comfortably.

These catfish are usually offered for sale as juvenile specimens at around 4" in length. The unsuspecting aquarist will have taken on more than he bargained for, while a genuine enthusiast will already know a bit about these fish and their requirements prior to their purchase. The colour of these fish is basically dark brown to black - hence the name Black Doradid. If you own one of these catfish, you will know that feeding time can be a rather wet experience, even with tight fitting cover glasses, or in my case an open topped pond! I have lost count of the number of soakings that I have had over the years!

I purchased my first Mother of Snails Catfish about fifteen years or so ago. The first one that I owned was around 10" long SL (25cm) and very rapidly outgrew a 72" x 18"x 18" aquarium. I eventually purchased a larger aquarium 72" x 24" x 36" and went on to keep this fish for a number of years. When the fish died from bacterial infection it was almost 28" in length, and would have required an even larger aquarium before long. This was really the main reason behind the construction of the tropical pond, although I must admit that I had not envisaged keeping 10 all at the same time.

The Mother of Snails Catfish belongs to the Family Doradidae, all of which originate from various locations throughout South America. Occasionally amongst imports of Oxydoras niger there are some slightly different specimens which tend to have black coloured fins and a grey coloured body. These so-called contaminants are Oxydoras holdeni. One of the main characteristics of the Doradids is the presence of thorn-like projections along the side of the body, which are known as scutes. These scutes are very sharp, so care should be taken when moving these fish. These razor sharp scutes give rise to another of the fishes common names - the ripsaw catfish. This name tends to me more commonly encountered in the US. Sometimes literature refers to the Doradids as "Talking Catfish" due to the fact that they can be heard to make audible noises, almost as if speaking to one another.

As yet, there are no records of these catfish having been successfully bred under aquarium conditions. Perhaps with the space available to my collection of these fascinating fish, it may just be a matter of time before I witness some kind of spawning activity. I will of course record my observations.

References:
Dr. Rudiger Riehl & Hans A. Baensch. Aquarium Atlas Vol. 2. (Baensch - Tetra Press 1993).
David Sands. Catfishes of the World Vol. 4 Aspredinidae, Doradidae & Loricariidae. (Dunure Publications 1984)
Gina Sandford and Richard Crow. Interpet Manual of Tankbusters (Salamander Books 1991).

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