Biotopes of India | The Western Ghats, Mountain Streams to Mangrove Swamps

Chris Englezou Biotope, Chris Englezou 5 Comments

It is the middle of the dry season in the Western Ghats; I am here in the mountains of southern India at 3000ft above sea level on the border of two states, Tamil Nadu and Kerala and I am surrounded by dense jungle. The temperature during the day is not yet scorching but reaches somewhere in the region of 34°C, the canopy keeps me mostly shaded but at night the temperature drops by more than 20°C and it can be a shock to the system. My surroundings are dry but are quite reminiscent of my time in the Amazon except jaguars and pumas are replaced by tigers and leopards, anacondas and bushmasters by pythons and cobras but nothing can quite replicate the majestic enormity of the ruler of this jungle, Elephas maximus indicus the Asian elephant. As I walk my way along a footpath of no more than twenty inches, the red dust emblazoned onto the tree trunks at my eye level and the periodic instances of dung tell me that the cavities I step into with each stride are the footprints of elephants; I am walking in the footsteps of giants.

Walking in the footsteps of wild elephants along this thin pathway on steep mountainous jungle terrain makes you appreciate the ability of these huge mammals to navigate the jungle so delicately.

I continue to follow my map which provided I plotted correctly should lead me to a small freshwater stream just above some steep waterfalls, it is a tributary of the Maruthapuzha River in the Chaliyar River drainage and it is above these falls that I want to investigate. The jungle is eerily silent other than for the calls of various birds and while it can often be a very tranquil experience, it is tainted with the bittersweet insecurity that you never know what lies ahead (or behind) you. The idea is to move with conviction, own your environment and emit that sense of synonymy with the jungle from every cell of your body; the jungle understands no language other than that of the body and fear becomes either fuel or failure.   As I carefully step my way down a steep and slippery ravine I see the shallow riffles of this undisturbed rivulet meandering through the jungle and as I walk my way along its path the crashing of the falls becomes more and more apparent. Under the shade of a colossal Artocarpus tree the stream widens and forms a rocky, leafy pool and in the central portion of the stream lies a long, intertwining filamentous algae dancing in the flow. There are also noticeably slower moving areas in the littoral zone under the tree and on the opposite side below some overhanging riparian shrubs. With the dense leaf litter, oxygenated flow and protective roots, this looks like a good place to find fish and sure enough, in a quick shimmer of iridescence I know I am in the right place.

The waterfall was pretty steep, possibly acting as an ecological barrier to some fish species.

I take a moment to prepare my equipment and tighten my shoe laces, there is nothing worse than losing a shoe in a metre of mud and so I proceed to move slowly into the shallow stream and as expected I am quickly knee deep in leaves and silt. My positioning however is good and after the initial scattering, my disturbance of the substrate begins to attract some of the small iridescent fish back towards me. At first glance, they appear to be a Danio species but I quickly realise they are juvenile Devario cf. malabaricus; some nettings through the slightly deeper and rockier areas bring out a wonderful adult-sized specimen which I quickly photograph and release. 

The sun penetrated the canopy here allowing a rich green filamentous algae to grow in the stream which Haludaria and Devario were using as protective cover.

The stream at this location was lined with layers upon layers of Artocarpus leaves – important safety for adult & juvenile fishes

Swimming alongside the Devario I observe young striped barbs which I suspect to be the Melon Barb Haludaria fasciata, but the markings are not quite right to what I have seen before as the fish are lacking the black stripe on the caudal peduncle, but H. fasciata is a highly variable species which has several regional forms exhibiting different patterning from place to place, so I assume I have the right species for the identification.

Mature Devario cf. malabaricus were present in this remote stream in great numbers and all were in great condition.

Juvenile Haludaria fasciata from the mountainous border of Tamil Nadu and Kerala with only three black stripes on the body

I collect a small striped individual from a shoal of about 50 or so fish, but then I see a quick flash of red with a hint of green just below a very large overhanging rock; it is a group of about 8-10 young males swimming together in full breeding colouration. I manage to capture one and take a photo before letting him return to his very important business. It is an interesting and aberrant form of H. fasciata at this location, but they are truly exceptional and sadly, the intensity of the red colour is reduced by at least fifty percent once outside of the water and my photos do not capture its true beauty.

This interesting and aberrant form of Haludaria fasciata is found occasionally in the aquarium hobby, all be it very rarely.

Nevertheless, I continue and after some time, in my last few dips of the net I manage to find the local predator, a very sweet juvenile Snakehead Channa cf. striata tucked away deep into the leaves. He reluctantly and unusually allows me to take a few photos and then swims hastily back into the substrate once released. I collect my things and head back to prepare for the 130 mile drive southwards to Vembanad Lake, a huge coastal brackish lake extending over sixty miles between Azheekkode and Alappuzha, it is the longest lake in all of India.

Reaching Vembanad Lake

From a relatively high vantage point, I observed a group of Humpacked Mahseer Hypselobarbus mussullah congregating to feed. H. mussulah are an endangered species and Vembanad Lake is a known refuge for them.

At the mouth of this stream leading into Vembanad lake I was able to observe one individual Channa marulius (centre shot) stalking and hunting young Hypselobarbus mussullah from behind and beneath rocks

Aside from fish species, Vembanad lake was also home to some sizeable and awe-inspiring estuarine crocodiles

On my way I stop over for one night in Kochi to give two talks at the Kerala University of Fisheries & Ocean Sciences on the importance of freshwater conservation – my personal journey from naturalist to conservationist and the role of more natural and sustainable alternative feed options in fish nutrition. I was stunned to be welcomed by over one hundred undergraduates, postgraduates, doctors and professors eagerly interested to hear my views and make a difference in their respective fields; the Q&A afterwards lasted almost as long as the talk!

The lecture attracted a great audience of undergraduates, postgraduates, doctors and professors all working in areas of aquatic conservation, fish nutrition and other specialisms

It was a huge honour to be invited to speak at Kerala University of Fisheries & Ocean Sciences

I was filled with a renewed motivation the next day and after reaching Alappuzha I stopped for some breakfast and waited to board one of the signature houseboats for one night – this night I’d be searching for brackish fishes and I was excited. We set off on the boat in the blistering heat of the mid day sun and travelled all the way from Kochi to the southern most area of the lake near Moonnatiinmugham about 35 river miles stopping for lunch and some sightseeing on the way. I passed by one of the local stores at the rivers edge, they had some freshly caught fish, crabs and prawns all frozen from the morning with the most notable being the Green Chromide Etroplus suratensis which is locally known as “Karimeen”. After returning to the boat with some fresh prawns and Karimeen for dinner, we docked for the night and had a hearty meal; then off I went into the darkness to see what aquatic treasures I could find. The vast majority of the lake is surrounded by large areas of agricultural land with coconut palm plantations and rice fields for as far as your eye can see. Since the roots of palms do not penetrate deeply enough to hold the river banks solidly in place (like the roots of established primary forest trees do), there are almost no areas of unaltered shoreline and they are all reinforced with large rocks to try to offset the erosion process. After walking for several hours and finding only stone walls and man-made channels for the rice paddies, I came across one very small piece of semi-natural shoreline between the wall and the river bank with a gravel-like substrate, some algae and many rocks. With my torch, hand net and camera I spent at least three hours in this tiny stretch of maybe two to three metres searching for fishes and came up with some interesting finds (considering). Species living here in this spot were Aplocheilus lineatus, a very nice black shrimp, probably a Caridina species with an orange tail, and a juvenile Channa marulius which jumped right out of my net and again out of my hand before I could get a photo – “the one that got away”. I was also able to observe Pseudosphromenus cupanus sleeping in the very shallowest parts between rocks, it is a species usually found in association with dense vegetation and so likely can be found in greater numbers in the rice fields. Water temperature was 28.9°C, pH was 7.2 and salinity was 0.1%; I returned to the boat to take notes and get some sleep.

The only stretch of remotely natural shoreline I could find for a great distance in this area was still home to quite a variety of species but in little number – imagine if the habitat was intact and thriving!

Despite the very unnatural habitat, I was able to find just this one individual Pseudosphromenus cupanus asleep among rocks and algae during the night time; nowadays the habitat of this gourami known as the Spiketail Paradisefish is mostly rice fields.

A closer look at Pseudosphromenus cupanus

This interesting black shrimp, possibly a Caridina species had a tiny speck of orange on it’s tail

We reached Alappuzha again at 8.30am and immediately I set off on the almost 100 mile drive to the town of Poovar in Thiruvanathapuram where I wanted to explore the brackish swamps in the lower Neyyar River. Situated in the centre of a thick mangrove forest the lower reaches of the Neyyar River are a truly iconic brackish habitat. When the average fish keeper thinks of brackish aquariums, we are usually confronted with thoughts of the same species, Tetraodon puffer fish, Monodactylus, Scatophagus and so on, but here in the estuarine zone of the Neyyar River I spend many hours over three days wandering through endless swamp entranced by the diversity.   I see both species which are new to me and those which are very familiar and in one pool a few dips with the net into the dense leaf litter brings out a very sweet Pseudosphromenus dayi and a very interesting Pseudogobiopsis oligactis. After some time finding only much of the same I realised that I’d need to employ a different method to catch some of the more open-water swimming fishes. Lacking a seine net I was forced to resort to the old tactic of “sit and wait”. These moments sitting in stillness and silence among nature are usually some of the best and where you learn the most, although I did almost die when a bright red and venomous coral snake fell from a tree directly into my lap! As with all creatures in the wild, he was more afraid than I was (and that’s quite a statement) and he quickly dipped below the water and swam for safety.   A short while later I take my opportunity and scoop up a netting of a few different species including a really stunning little shoaling cyprinid Horadandia atukorali, and the tiniest transparent ricefish Oryzias setnai, also known as the Indian Glaskilli or the Miniature Indian Ricefish; I also had one mature male Aplocheilus lineatus with the most striking colours and big beautiful green eyes.

Shallow swamps form a lot of the lower Neyyar River mangrove habitat, they are rich in macrophytes and semi-aquatic plants, lots of leaf litter and are very slightly saline.

Some of the submerged vegetation in the mangrove swamps

This beautiful cyprinid Horadandia atukorali was present in large shoals in the mangrove swamps of the Neyyar River and has outstanding green iridescence.


The tiniest fish I was able to capture and photograph after much difficulty, was this very minute ricefish species Oryzias setnai. They swim in small shoals near the surface and are so tiny that they could easily be overlooked if not for the subtle ripples they cause on water

A stunning male Aplocheilus lineatus with striking green eyes from the mangrove swamps of the lower Neyyar River; this species was present in great numbers here.

The Brown Spiketail Paradisefish Pseudosphromenus dayi (juvenile) showing it’s trademark two lateral lines along the head and body which separate it from its congener P. cupanus

Other species observed here but not captured were Dawkinsia filamentosa, Awaous grammepomus and breeding pairs of the Green Chromide Etroplus suratensis; the two former I observed predating the fry of the latter and there were also a small number of Haludaria fasciata here too.   At night time, I was able to do some collecting and make some observations of other fishes including the lovable Orange Chromide Pseudetroplus maculatus which I found sleeping in the shallows much like how Satanoperca and other cichlids do in the Amazon and on only one or two occasions I got a very quick glimpse of what looked like a richly red coloured Caridina sp which will remain a mystery; a bonus was that I caught a very lucky photo of the Pseudogobiopsis courtship taking place in darkness.

The iconic and lovable Orange Chromide Pseudetroplus maculatus was present in good numbers here and was similar to Satanaoperca I had observed in the Amazon – not only in it’s morphology, but also in its habit of sleeping among the leaves and twigs in the very shallowest edges to avoid predation.

I was very lucky to come across a pair of Pseudogobiopsis oligactis courting in the darkness during one of my night observations; it was difficult to capture a good photo but this gives an idea.

Water temperature here in the area was around 27.3°C, pH was 6.8, TDS was 503mg/l, salinity was around 1.2% and interestingly there was a very low detection (0.1mg/l) of nitrite in the water, which research by G. Ajesh et al (2003) suggests increases during the monsoon season rains; I suspect this could possibly be due to the use of pesticides and fertilisers by the agricultural sector. After another good night of sleep interrupted only by the high-pitched songs of gratitude from the mosquitoes singing into my ears, I took an opportunity to photograph a few other interesting non-aquatic creatures and then made my way to the airport for the long journey home.

I was lucky to get a quick photo of this very sweet and gorgeously coloured lizard, probably a Calotes species.

A stunning Dysphania cf. fenestrata moth spreads its beautiful wings and shows off its colours.

Rhyothemis variegata were present in very large groups and congregated specifically around Anacardium trees during the day, which consequently were also a popular spot for large fruit bats at night.

Plastic pollution like this was a huge problem I encountered at every single stop during my time in Southern India, many times covering entire water surfaces…  I’ve debated ideas for solving this problem ever since…

India is unforgettable, it is a contrastingly beautiful and shocking place with such rich biodiversity surrounded by an ever encroaching expansion of construction, agriculture and pasture, disposal of plastic is an irrefutable disaster. I leave here enlightened, inspired and grateful but concerned for the places I have seen which will probably never be seen again.

Comments 5

  1. Hello wonderfull job. I like to work with you I am also working with freshwater river fish in my native country Ecuador.

  2. Nice one . your style of writing is good .iam from Kerala , Gods own country.we have around 290 freshwater fishes .some of them lives in brackish water too .

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