Basically speaking, the spiny eels of Asia can be divided in two groups: the small species belonging to the genus Macrognathus that reach usually only 10-15 cm total length and the large species of the genus Mastacembelus that grow to a length of more than 40 cm (maximum length reported: 100 cm).

 

We received a shipment of spiny eels from Thailand that confused us a bit regarding the determination of the species. On the one hand the fish looked very similar to Macrognathus circumcinctus, on the other hand they looked somehow different. The riddle was solved by researching the synonyms of M. circumcinctus. One of these species regarded currently as synonymous with M. circumcinctus is a species described as M. taeniagaster from Thailand. Checking the original description of the latter proofed that we had obtained exactly that fish. Of course this is neither the place nor the medium to decide wether M. taeniagaster and M. circumcinctus represent two different species in the zoological sense. But it is a fact that they look a bit different. The main difference is the presence of a row of ocelli on the base of the dorsal fin in M. taeniagaster which is lacking in M. circumcinctus.

 

Macrognathus taeniagaster is able to change the colour very fast. The very same fish can be uniformly colored beige in the one moment and in the next can show an almost white back and a dark belly.

 

Keeping these spiny eels is very easy. The fish like the company of their own kind and often share the same hiding place. Males stay smaller than the females and are much more slim. Macrognathus feed readily on any type of frozen and live fishfood. Very small fish are taken as food, but in general the spiny eels are very peaceful against tankmates and are very suitable for community tanks. The fish spawn near the water surface in the roots of swimming fern etc.. It is possible to breed these fish in aquaria, but this is rarely done.

 

Photos & Text Frank Schäfer

 

 

 

 

 

 

 

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