BOOK REVIEW: Observations On "The Cichlid Aquarium" (Dr Paul Loiselle, Tetra Press) by Andrew Boyd

 

The breeding notes revealed a blatantly obvious yet hitherto unthought of (by me) theory: Why big Cichlids tend to have more male offspring than female. This theory rests upon three well-known facts:

 

  (a)  Big Cichlids (especially the Guapotes of subgenus Nandopsis such as dovii and managuense) have large spawns, often numbering 500-1000 fry,

 

  (b)  These fry tend to sibling cannibalism, ie they eattheir brothers and sisters, and

 

  (c)  Male fry tend to grow faster than their sisters.

 

The net result? The bigger male fry eat a lot of the small female fry. What to do about it? suppose that grouping the fry by size would help if not eradicate this problem. Stick all the 5-10mm fry in one tank, all the 11-20mm fry in another, and weed out the one "super-fry" that invariably grows ten times as fast as the others. A divided tank would work just as well, as long as filtration is taken care of on both sides of the barrier (unless it is a permeable one). Does this situation have an analog in the raising of Australian and new Guinean Rainbowfishes? Possibly, but it would not be as severe, as the intra-sibling cannibalism is nowhere near as bad.

 

Another point of note is the division of Cichlids by spawning method (this being an indicator of likely behaviour patterns and therefore having a bearing on how they are kept). I had previously thought that the Cichlidae could be neatly divided into Mouthbrooders and Egglayers, but now I know that this is not the case. Not all Mouthbrooders act alike, a gross over-simplification on my part. Dr Loiselle divides spawning method into Monogamous (single partner) and Polygamous (multiple partner) with Polygamous Cichlids being further divided into Haremically Polygynous (single male with multiple female partners, a state that some Egglayers attain, not just mbuna) and Openly Polygamous. At this stage it gets a bit complex, with further divisions based on behavioural characteristics, and if you are interested then I suggest that you read the book yourself.

 

Rest assured that if you are interested in breeding Cichlids, or even in just successfully keeping them alive, (the two often go hand in hand) then you should look at this book. I have kept a few species of the Nasty Biting Fish over the years and a lot of what Dr Loiselle says makes perfect sense and explains losses of fish and their fry owing to incorrect filtration, feeding, or housing. Members with a keen interest in Cichlid keeping would probably save a lot of money in the long run by buying a copy of this book.

 

Dr Loiselle has a good writing style, easy to understand, although the less technically minded might need to keep a dictionary handy to comprehend the liberal sprinkling of ichthyological and behavioural biology terms.

 

It is just another of the fine books available for nothing from your club library on monthly loan.