After the Monsoon: Fish of the Emerald Forests of Thailand

Author: Stan Sung

Journey with fish collector extraordinaire Stan Sung through the jungles, swamps, and streams of Thailand as he explores the habitat for various fishes and other wildlife.

Journeying Through Thailand

After the monsoon, the jungled hills were vibrantly green. This was my third trip to Thailand and this wonderful country is fast becoming one of my favorite places to visit. Mark Young, Nont Intarapkdee, Korn Petchnarong, and I continued driving along the coastal highway in a heavy tropical downpour. I looked down at my tingling ankle and noticed that the leech bites I got at our previous site, Baan Mai Khao, were bleeding profusely. The trickling wounds caused a small puddle of blood to develop on the floor mat of the car. I looked over at Korn, who had bleeding toes as well. I had to laugh at myself, for I was back, collecting in Southeastern Asia and tromping through leech-infested rice paddies once more.

This is sheer paradise for me, as collecting tropical fish in exotic lands is what occupies most of my thoughts and dreams. The leech and mosquito bites didn’t matter, as we were driving deep into the rainforest to collect in a rushing forest stream. I couldn’t wait to see what we would come up with.

We wound through small villages and intermittent jungles as we continued north on Highway 4. The Andaman Sea was to our left. Only once in a while would we get a glimpse of the ocean because of the dense foliage on both sides of the road. We drove through Khao Lak, one of the areas hit hardest by the 2004 tsunami. Here alone this town suffered hundreds if not thousands of casualties. An enormous land-locked ship a couple of miles inland from the sea was the only major reminder of the disaster of 10 months previous. Before turning inland into the forests, we passed by mass developments that Habitat for Humanity has built for the displaced inhabitants of Khao Lak and surrounding areas. Soon the asphalt turned into a bright red dirt road. We continued our way into the mist-shrouded Khao Lak Laem Ru National Park. We would take the next couple of hours collecting and exploring the seldom visited Ton Chongfah Waterfall.

A Highland Jungle Stream

Hiking up into the dense foliage, we soon heard the rushing water beyond the very thick undergrowth. Eventually we found ourselves standing knee deep in an idyllic tropical stream. Water as clear as glass flowed swiftly over stones of different sizes. The submersed stones appeared dark gray, while some of the exposed stones along the banks were bright green. Although beautiful, the lime green moss covering the rocks was dangerously slippery, making our hike up the waterfall challenging. A great dark forest loomed over us.

The gushing rains of the monsoon pounded upon us, making a tremendously loud rumble as the torrents hit the leafy canopy overhead. Carrying my castnet, dipnet, and buckets while trying to keep from dropping or soaking my camera was difficult. I decided to leave my camera gear wrapped in a plastic bag along the bank while I tried to collect some of the small, swift fish darting in the shallow pools along the shore. Danio kerri were very easily scooped up with a swift pass of the dipnet in water that was only 3 or 4 inches deep. I used one hand to scoop the net and the other to corral the danios toward it. In about five minutes I had a dozen beautiful blue-and-pink danios in hand.

Danio kerri is a small cyprinid closely related to the common pearl danio D. albolineatusD. kerri deserve to be popular in the aquarium industry, as they are more boldly colored and a bit bulkier than D. albolineatus. They make adaptable, peaceful inhabitants for the home aquarium. As a testimony to their hardiness, I kept the entire group of D. kerri in a “breather bag” for one week before bringing them home and did not lose a single one!

We eventually made our way up some elephant-sized boulders and past the rushing waterfall. On the other side of the cascades was a series of rocky pools where we threw our castnets. Although the stream bed was rocky, it was easy to use that net because the water was so clear. Even if it became snagged on the submerged rocks, it was simple to untangle because the clarity of the water allowed us to see things so well.

The beautiful blue, pink, and yellow Devario regina came up next in our nets. These colorful fish were at least 4 inches long and deep bodied. Other speed demons we were able to capture were Neolissochilus stracheyi and Tor tambroides. Both are powerful, current-loving cyprinids that possess giant armored scales.

In Ton Chongfah we were able to collect Puntius orphoides, one of my favorite cyprinids. This delightful aquarium inhabitant is found throughout Thailand. Superficially they may look like a chunkier, round-headed tinfoil barb, but upon closer inspection they are more colorful, boasting crimson fins and eyes, rows of black dots along the flanks, and a sharp, black-edged tail. What really give this species away are the crimson “cheeks” and a pair of black bars—one on the operculum and one just behind it.

P. orphoides is completely harmless to other aquarium inhabitants in captivity. They are greedy, however, and will gorge themselves and put away a tremendous amount of food. They may put a strain on the aquarium’s filtration system and grow swiftly to around 10 inches in length. Wonderful tadpoles with red spots, Schistura loaches, and turtles with golden eyes rounded out our catch in the jungles at Ton Chong Fah.

Steamy Lowland Swamps

At another swamp I decided to scoop the net in the flooded grass along the muddy shore. Tiny red-finned Rasbora borapetensisRasbora trilineataAplocheilus panchaxBetta imbellis, and Trichopsis vittata quickly filled our collecting bucket. We even managed to capture some eels—Mastacembelus armatusMacrognathus siamensis, and Monopterus albus holed up in some PVC pipes. We sampled many of the swamps and lakes along Highway 4.

 “The eyes shine like dewdrops on a lotus leaf” is an image fanciers of the rare Korat cat use to describe the breed; I never understood this analogy until I saw the clear, globular drops of dew shining in the early morning sun along the northbound highway. It was brilliant to see the silvery water droplets glistening on top of wide green lotus leaves. From under the pink lotus blooms and round leaves, we sampled other great aquarium subjects such as Rasbora rubrodorsalisMicrorasbora kubotai, leaf fish Nandus nebulosusPristolepis fasciata, and Badis siamensis.

Betta Habitat

An avid fighting-betta hobbyist, Korn Petchnarong ignores the Betta imbellis that live naturally all around his property since theyare not pugnacious enough; only his coveted B. splendens champions from Bangkok or Malaysia are kept and propagated. In Baan Mai Khao there are open marsh areas surrounded by palms and rubber tree plantations. Along with Mark Young and Korn Petchnarong, Nont Intarapkdee also came along with us to collect fish. Although not particularly interested in fish, Nont (who is Korn’s brother-in-law) proved to be an excellent translator, as he was fluent in both English and Thai.

As we walked among the densely grown trees, I caught a glimpse of aquatic-lily-clad meadows through the foliage. We sampled several ponds and lakes in Baan Mai Khao. The Betta imbellis were easily scooped up along the heavily vegetated banks. We meticulously searched for the betta bubblenests clustered around blades of aquatic grass. Whenever we spotted the nest, a floating raft of dirty bubbles on the water’s surface, we scooped up gently from underneath and would usually come up with either B. imbellis or Trichopsis vittata, called “Plaklim” in Thai.

Betta imbellis live among the grasses with such fish as Rasbora borapetensisAplocheilus panchax“Plahuakour,” and Trichopsis vittata. The bettas from this area of Thailand are lighter (yellowish) in quiescent suit than the B. imbellis I have collected in Western Malaysia. When they are in their aggressive moods, they are the same glittering black, emerald, and crimson fish as their southern cousins. The leeches were downright ravenous here in Baan Mai Khao. Within seconds of stepping into the water, several leeches were latched onto our feet, sucking away! Bleeding profusely from painless leech bites, we continued our fish collections deep into the surrounding jungles.

The area behind Korn and Nont’s houses at Baan Mai Khao is a large field of marshes and swamps. Here the rubber and palm plantations skirted in and out of tall forests. Even early in the morning the heat was tremendous. We walked through the trees to a large lake with reed-lined banks. Korn and I waded out to retrieve a submersed wooden fish trap that they had placed among the reed stalks the night before. Inside the trap were a couple of turtles, very large (6-inch) snakeskin gouramis Trichogaster pectoralis, climbing perch Anabas testudineus, knifefish Notopterus notopterus, and walking cats Clarias batrachus. I took some photos of these larger food fish and decided to investigate the nearby lotus ponds for some of the smaller tropical jewels for the aquarium.

In the Mangrove Forest

The Ao Phang Nga surely has some of the most dramatic scenery in all of Asia. Covering an area of around 400 square kilometers along the coast between Phuket and Krabi is a mangrove-lined bay with incredible karst limestone formations. These formations are up to 150 feet high and are rugged and jungle covered. While I did not do any actual fish collecting in these mangroves, we did observe many fish and animals in a beautiful setting.

We paddled through low-lying mangrove forests in sea canoes. The tiny crafts are perfect for slithering along the fringes of the craggy limestone formations. “Hongs” are secret tidal lagoons only accessed through tunnels that lead to the karst’s central pool. A secret room or chamber is found inside, in the heart of the karst. Looking upwards, the walls are draped in vines where bats and flying foxes flit about before the tropical sky.

The canoes were also small enough for us to go between the thick stands of the mangrove forest. As we paddled quietly through the dark green water we caught glimpses of aquarium favorites like needlenose gars Xenentodon cancila, silver datnioides Datnioides polota, barramundi Lates calcarifer, archer fish Toxotes chatareus, green scats Scatophagus argus, and the ever-present mudskippers Periophthalmus barbarus.

One fish that we spotted in the mangrove forests was the Pacific tarpon Megalops cyprinoides, which we had also collected in lakes along Highway 4 on the mainland. This is one of my favorite fishes we managed to find in our nets. M. cyprinoides is a hardy, prehistoric-looking fish that is robust and peaceful (with fishes they cannot cram into their large mouths). They make extraordinary tankbusters with their streamlined forms and large glassy eyes. The head is quite armored, and they even have up-turned mouths, like arowanas. Young fish appear to be at home in pure fresh water. The larger individuals probably appreciate a little salt in their water, although large specimens over 3 feet are found in the surrounding freshwater lakes fairly frequently. My tarpons made it home in perfect condition and feed greedily on frozen brine shrimp, bloodworms, and mysis. So far they will only feed in the middle of the water column; I have not observed them feeding off the bottom or the surface.

More Mist-Shrouded Jungles

Big raindrops splattered on the windshield as we passed mile after mile of verdant jungle. Once in a while the gleaming gold gilding of a temple spire peeked out above the thick forest. Having worked up a tremendous hunger at the waterfall, we stopped at a tiny village to take lunch. Nont wanted us to sample the delicious essence of Southern Thai cooking. The food was very fragrant and had a sharp peppery zest to it. He also played traditional Thai folk songs on the car radio so that we received a genuine Thai sensory experience.

With the strums of traditional instruments we went along up the road. We veered inland on Highway 4090 right before Khao Sok National Park. The terrain became hilly, with shrouds of white mist enveloping the rich green mountains. We eventually made our way to the Muang Kirirath River. The river was swollen, muddy, and overflowing from the heavy rains of that afternoon. We decided to try some swampy overflow ponds up the street a few hundred feet. It was muddy going there, so we threw castnets from the bank rather than having to fight through the sludge.

First to come up in our nets was Cyclocheilichthys repasson. All of the Cyclocheilichthys species (with the colorful C. apogon being the most common) make fantastic aquarium subjects. They are an assemblage of regal cyprinids with tall fins and attractive patterns. The Cyclocheilichthys are medium-size fish that behave very peaceably in captivity.

My tropical-fish-collecting hobby has taken me to Southeast Asia time and again in the last several years. Prior to visiting these countries, I discounted the many species of cyprinids from Asia as mostly boring silver fish that make uninteresting aquarium subjects. Boy, was I wrong! I have been introduced to an entire world of rare, unique, obscure, and interesting fishes that can be kept in the aquarium. The Hampala macrolepidota from Muang Kirirath is yet another big showy cyprinid for the monster-fish collector. Small glassfish Parambassis siamensis rounded off our catch on Highway 4090.

Our final collecting site of the day was the beautifully majestic lake at Baan Lampee by Route 4240. Great stands of ferns and bamboo lined the lake. To the left there was a small picturesque settlement and the lake mirrored the silvery white and gray sky perfectly. The common Aplocheilus panchax are always among the first fishes spotted while surveying each site. They are usually found along shallow banks and are easy to see because of their surface-dwelling lifestyle and the silver “killi spot” on the top of their heads. Many times only the silver spots are visible from above. With a quick pass of the dipnet, Nont quickly yielded us a small colony of the attractive blue and orange killies. Datnioides microlepis was also found here in Baan Lampee. These are among the most cryptic of fishes and we could only find them in areas with thickets of vines and submerged tree trunks.

Beyond the Great City of Bangkok

The grand Chao Phraya River runs among concrete buildings, twisting canals, sky trains, and zooming tuk-tuks. Everyday goods are plied up and down the lifeblood of Thailand’s capital. The modern city falls away as one cruises north up the Chao Phraya River. Eventually only small shacks and exotic wats (temples) appear sporadically. Because of overfishing with gill nets and pollution, many of the fishes that hail from this river system are declining.

We headed east to try to get away from the congestion of the sprawling city. We took the road toward Mae Nam Bang Pakong, where the concrete jungle slowly gave way to a serene sunbathed countryside. We found a wide range of habitats in this region. The larger rivers and canals were still turbid from the pounding monsoon showers of the night before.

Walking up to the bank I initially surveyed a catch that some villagers had made. Great specimens of the giant Thai stingray Himantura chaophraya were proudly shown to me. These leathery beasts were only half grown at 3 feet long! A jagged-toothed gaping-mouthed denizen of the Chao Phraya River System is Macrochirichthys macrochirus. These toothy, silvery predators are much loved by monster-fish enthusiasts. M. macrochirus is sporadically imported at around 4 or 5 inches in length and will eventually grow into a 2-foot compressed and streamlined predator. Labeo dyocheilus is a large “shark” captured by the fishermen. Jumbo catfish Pangasius hypophthalmus rounded out the villagers early morning catch.

Korn and Nont led me to a weed-lined swamp where we followed a bright yellow string into thigh-deep water, and Korn found a PVC tube attached. He gently placed a dipnet over one opening of the tube and lifted the 5-foot section from the water. Out poured specimens of tiretrack eels Mastacembelus armatusand fire eels M. erythrotaenia.

What a kick it was to see these staple fish of the aquarium trade thrashing about in the awaiting net. The fire eel must be one of the most exotic and beautiful of the many mastacembelids available to aquarists. When mature, these mostly black and scarlet fish are truly eye catching. I have heard reports that the fire eel is susceptible to bacterial skin infections in the home aquarium. I do not know if I have just been fortunate, but I have not had any such problems with my captive fire eels. I suspect that newly imported fire eels have been abused and are thus susceptible to a number of diseases. The jumbo show-size specimens, often imported at over 12 inches, may be more difficult to adapt to a captive environment than smaller individuals. I would suggest purchasing brightly colored fish no larger than around 6 inches in length.

The same goes for another Thai eel, Mastacembelus alboguttatus, the spectacular gold coin eel. I have collected these in large numbers in neighboring Burma, and I have noticed that the small specimens have adapted much quicker once brought home than the large show specimens. Pass up emaciated, blotchy specimens. The younger eels should adapt quickly to a diet of frozen mysis, brine shrimp, and bloodworms. As they grow larger they will appreciate size-appropriate foods, so you would want to replace mysis with krill or market shrimp, and bloodworms with earthworms, etc. Fire eels will grow very quickly into outgoing robust specimens, which no large-fish enthusiast should be without.

Another black and red staple of the aquarium hobby is the red tailed shark Epalzeorhynchos bicolor. We harvested these cyprinids out of traps made of reeds. A few other classic aquarium fish were netted out of adjacent blackwater ponds and rice paddies. The pearl gourami Trichogaster leerii and moonlight gourami Trichogaster microlepis are both commonly found in the hobby and seldom collected in nature. Their cousins, the blue gourami Trichogaster trichopterus and the snakeskin gourami Trichogaster pectoralis, are wide-ranging species that usually dominate the steamy ponds preferred by the anabantids. The pearl gouramis are a little more common in the blackwater habitats. Prime specimens of glowing red and lacy violet colors were found glistening in our nets.

Some Rare Cyprinids

We did chance upon some juvenile specimens of Catlocarpio siamensis. These are comical-looking chaps with heads that appear too large for their bodies. The silvery young fish are found over mud bottoms in sluggish water. They are detritivores that repeatedly scoop up the bottom sediment in search of food items. In an aquarium they can be a real challenge to keep with other fishes, as they are out-competed by more boisterous feeders. Smaller specimens are best kept alone or with other very slow feeding fish such as Chinese high-fin sharks Myxocyprinus asiaticus.

I have had success in raising baby catlos with tiny fish such as rasboras, killies, and danios. These smaller fish usually can’t eat a great quantity of food, and the excess food falls to the bottom of the aquarium where the Catlocarpio can graze at their leisure. Frozen mysis and vegetable flakes appear to be their favorite food items. The catlos are inept predators at best, and even large specimens can be placed with the smaller community fishes. The slender, silver juvenile fish will grow into very large black fish with a white throat and white-edged scales. Also, this species is said to grow upwards of 8 feet in length! The giant Siamese carp is one of the cyprinids in which the numbers in nature have drastically declined, most likely due to over-fishing.

Another beautiful cyprinid from the Chao Phraya Basin is Puntioplites proctozystron. This 10-inch silver and light brown fish possesses majestically elongated dorsal and anal fins that remind me of a young pompano. This is a spirited aquarium inhabitant and they constantly chase one another around and display to each other. They do a peculiar “sideways shuffle,” much like the marine surgeonfish do when quarrelling. This harmless squabbling appears mostly to be bluff. Their southern cousin, Puntioplites bulu, is said to be on the verge of extinction (if not already extinct) in nature. I already have a trip planned later in the year to investigate the Mae Nam Ta Pi River system in hopes of finding a viable population of P. bulu still in existence.

Probarbus jullieni is commonly called either Jullien’s golden barb or golden price barb in Thailand’s aquarium trade. We managed to catch some young of these fish with a castnet. Because this is an endangered species protected under “CITES Appendix I” we photographed them and returned them to where they came from. Despite having a thoroughly protected status, they are common aquarium fish in their homeland. The Ambassador Hotel has a large tank in their lobby in which its only inhabitants are several beautiful examples of Jullien’s golden barb. At the aquarium shops, small individuals are frequently sold, although sadly they are usually in poor condition and are quite emaciated. These flashy barbs have very fast metabolisms and need frequent feedings when young in order to stay healthy. On the plus side is that P. jullieni appears to be a more competitive feeder than some of the other native species (such as Catlocarpio siamensis) in aquaria. Should you ever own some of these fishes (if you reside in Thailand that is), it is important to know that they only take food off the bottom of the aquarium.

A hardy, active, and colorful cyprinid that should be more frequently imported is Opsarius pulchellus. These are frantic little fish handsomely garbed in yellow and blue with a red dorsal fin to boot. The 3-inch O. pulchellus males constantly mock battle one another, their gills and fins flared.

The final rare cyprinid I would like to highlight here is Bangana behri. This is a large, aggressive show fish, and the mature males develop a spectacular nuchal hump. B. behri has a unique, under-slung mouth with an exaggerated and very thick upper lip. This combination of characteristics provides for a very different looking fish. They are wonderful algae removers in aquariums, as they will roughly skirt objects in the aquarium with their mouths in short, quick bursts. Bangana behri is found in the north of Thailand and makes an esteemed aquarium subject for those interested in the native fishes of Thailand.


The entire expedition was a great success, with no mortalities reported among the fish we brought back. I must have got some sort of nasty microbes through my leech and mosquito bites, though, because my foot became infected and swelled up like a dinner roll in the oven! It was not a lot of fun going straight from the airport (after flying for 21 hours) to the local acute care center. With a couple of injections and a week of antibiotics, the infection cleared up. This was the only negative of the trip, and I take full responsibility for foolishly going into questionable water with open sores. This was a great reminder to me that no matter how hot it is, rubber boots or waders are mandatory when entering into dirty, stagnant fresh water. On my next collecting trip to Asia, I will be sure to bring antibiotics and those miserable waders.


I would like to say thanks to Mr. Nonthachai Intarapkdee and Mr. Korn Petchnarong of Baan Mai Khao for their assistance in collecting fishes in the south. They shared their favorite traditional music, authentic feasts, first-hand accounts of the tsunami, and friendship with us. They added another dimension and so much more appreciation to our journey through Thailand.

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