Etroplus canarensis - The Canara Pearlspot

By Jim Dawson

Etroplus canarensis was first described by Day in 1877, it was then lost to science and the aquarium hobby till 1997. In the intervening years from description to rediscovery there is no known record of it being seen or collected. When it was rediscovered it was located only in a short stretch of approximatly three kilometers of the Netravathi river in Canara Province in India. Since then it has also been found in the Karnataka and Kumaradhra river systems. The very limited area that E. canarensis inhabits makes it not only very rare but potentially extremely vulnerable to exploitation, natural disasters and intervention by man(ie hydro electric projects). In 1999 limited quantities started to be exported for the aquarium trade, this has risen considerably over the years but not as far as I am aware to a dangerous level. The status of Etroplus canarensis on the endangered species list is not yet stated as far as I can ascertain.

A group of Etroplus canarensis in the authors tank.

Taxonomy Also known as the Canara Pearlspot and the Roman numeral cichlid and locally in India as the Rat nose Etroplus canarensis takes it's name from the province of Canara rather that the discoverers name. E. canarensis is one of a group of three Asian cichlids, the other members being E. maculatus (Orange chromide) and E. suratensis (Green chromide).

Sexual dimorphism There is no external sexual dimorphism. In the aquarium after two and a half years of owning them I can not even guess the sex of my fish with the possible exception of of the males being the larger fish.

Distribution Severely limited, found only in Canara Province in Southern India and three river systems within the Province, the Netravathi, the Karnataka and the Kumaradhara rivers.

Ecology The river systems that form the home range of E. canarensis have two yearly phases. In the dry season they are slow moving but not sluggish and are oxygen rich and they range from two to four feet in depth. There is an article by Subramian dated 2005 that gives some very specific temperature readings, taken on a collecting trip he made in the dry season. He notes that at noon in the Netravathi river the water temperature was 90.5 deg F (32.6 deg C) and in the Kumardhara river at 1800 hrs the water temperature was 91.6 deg F (33.1 deg C). The mean pH over the river systems is approx 6.5 with very little hardness. As far as I can find there is no data relating to either temperature or hardness of the river systems in the wet monsoon, it can only be assumed that there is a drop in both temperature and hardness due to the very heavy rains. The bottom of the rivers are a mixed habitat with rocks, sand, gravel and branches from trees predominating, in the dry season there will be a build up of detritus due to the falling water level and the flow rate slowing, but in the wet season the rivers increase in depth and the flow rate will scour the bottoms giving a quite different environment.

Remarks I first started collecting Etroplus canarensis some two and a half years ago and have slowly built up from an initial group of six to fifteen individuals. Initially I housed them in a four foot tank and using the information available at the time used a thick layer of heavy sand as the basic substrate and then used large smooth pebbles and bogwood to try and imitate their natural habitat, the first group settled in to this environment very well so I have maintained this set up to date. From the information given by Subramian I assessed that these fish would need a high turnover in the aquarium, a high oxygen content to the water and no pollution at all. To achieve this I used a Eheim 2217 filled with sintered glass media at one end of the tank and a powerful internal filter at the other, the internal filter was mainly for water circulation and to ensure there were no dead spots in the tank. I have now upgraded the tank to a 5 x 2 x 2 which has a built in filter filled with bioballs, ceramic tubes, sintered glass media and floss at one end and at the other end is the original Eheim 2217. There is also a 1200 LPH internal filter that is aimed at the surface with the job of ensuring a good oxygen exchange. The turn over from the three filters I use in their current home is approximately 3500 LPH and they seem to thrive on it.

Size seems to be slightly in debate as well with most references giving a size of 11 / 12 cms however there is one reference that says there is a preserved specimen in India at closer to 20 cms. From my own experience I would be inclined to go with the 11 / 12 cms size.


Diet was also a problem when I first got these fish, information was so scarce it was unbelievable. I started using a mixture of spirulina flake, mysis shrimp and a very small amount of bloodworm. I based this diet on the fact that in the wild E.canarensis had been observed feeding on algae covered rocks and that small shrimp and bloodworm would occur naturally in the river systems. I'm glad to say this worked, the loss of my first six fish would have been devastating not to say expensive! I have now added chopped mussel and prawn to the diet and also use a small amount of sinking cat fish pellets. This fish does eat algae and plant so if you are going to give it a planted aquarium then only use hard leafed plants such as Java fern(Microsorium pteropus). I occasionally drop in courgette for a change and this goes down well as does lettuce and cucumber, however be sure to clear the residue out of the tank before it becomes a pollutant.

When I started researching how to keep these fish the few small bits of information available indicated a shoaling fish which was why I went for a group of six rather that trying to pick a pair. Matt Clarke's article in Practical Fishkeeping was the best indicator at the time of it being a shoaling fish. My subsequent build up of the group size to fifteen confirms these are by nature a shoaling fish, in fact if one gets separated from the main group it quickly returns.

Breeding in the aquarium is rare there are only two records that I am aware of one in the USA and one in India. In the USA Tim Dooling in San Diego bred them in around 2005/2006 and unfortunately I have lost the reference to the Indian success. By breeding I mean that the fish have spawned and raised viable young, there are a number of spawns recorded without hatching occurring either because the eggs were not fertile or the parents ate the eggs before they hatched. From the available detailed information, which is scarce, temperature has to play a part in the breeding cycle of E. canarensis. The best estimate is the fish spawn as the wet monsoon comes to an end so one possible way to induce spawning is to raise the temperature slowly to approximately 29 to 30 deg C, leave it there for a few weeks and then give the tank a cold water change and allow the temperature to rise slowly, this may just imitate nature.

Tankmates are also a problem as E. canarensis are expensive and rare and a bad call with a tank mate will spell disaster. I eventually went for Puntius dennisoni an the basis they occur naturally with E. canarensis. As I use sand as substrate and my group show very little interest in turning over the substrate I have added a group of eight Corydoras adolfi just to keep the sand in good order and save me from disturbing the fish by manually turning the sand (not a purist move but a practicable one).

The basic nature of E. canarensis is non aggressive and verges on the shy side. However given sufficient space and cover in the aquarium coupled with a suitable non aggressive tankmate it ceases to be shy and forages round the tank the whole time the lights are on.

I have found Etroplus canarensis to be a very versatile fish, there is no way that I can imitate it's natural water conditions, living as I do in a very hard water area. In fact I suspect that if I had tried that route I may well have lost the lot as I would not have been able to maintain a very stable set of conditions that they seem to thrive in. Another observation I have made over the time I have kept these fish is they are slow growers and this could well affect their ability to breed, certainly I don't think they will breed at under three years. Within the UK I am aware of only two substantial groups of E.canarensis, apart from my own, and of several people who are keeping them in threes and fours. It is my opinion that it is vital we keep in touch and eventually get a captive breeding programme going to prevent over fishing in the wild and to this end I will respond to any e-mails or phone calls on the subject of E.canarensis and do my best to help.

Thanks to Jim Dawson for this Article , all pictures are © Jim Dawson