Unnamed spring close to lake Inle, Myanmar
_ place in Biotope Aquarium Design Contest 2019
Volume: 96 L
Dimensions: 80×30×40 cm
List of fishes: Fishs: Celestichthys erithromicron and Sawbwa resplendens
Invertebrates: Taia naticoides, Brotia herculea, Indoplanorbis exustus, Melanoides tuberculata, Corbicula fluminea
List of plants: Hydrocotyle sp., Nymphoides hydrophylla, Rotala rotundifolia, Ludwigia repens, Spirodela polyrhiza, Salvinia cucullata, Utricularia gibba, Fissidens fontanus, Colocasia esculenta, Ipomoea aquatica.
Description of decorations: At the right of the tank, two pieces of bogwood and several branches of
corkscrew willow mimic an old decaying stump. The huge taro tuber is hidden behind the bogwood. On the right, some clear rocks mimic the limestone blocks found in the Shan Hills. Both wood and stones from the tank are replicated, but bigger, behind the glass, to add depth in addition to a blue-green background. The substrate is fine river sand “sable de Loire” dirted with some Aquabasis Plus. Some Corbicula fluminea and Brotia herculea shells are displayes on it.
Description of equipment: A single DIY 1055lm LED spot lights the aquarium above the center, causing the plants to converge to it. A small heater is adjusted to 25°C on winter. There is no filter or pump, the nitrogen waste is consumed by the plants.
Water parameters: Temperature is above 25°C in winter and equal to room’s temperature the rest of the year. The pH is stable between 7 to 7.5. Du to artificial periods of slight drought and rain the conductivity is variable, but kept above 50µS/cm.
Additional info: It’s a second hand tank, so the glass is scratched everywhere and permanently damaged at the front glass, making it blurry at some points.
A similar tank was working for five years and all his content was moved to this one recently instead of moving the whole aquarium.
INFORMATION ABOUT BIOTOPE
Description of the area surrounding the biotope: Lake Inle is a polymictic lake located in the southern Shan State in Myanmar, 420 kilometers northeast of Yangon and is surrounded by rice fields, forests, peat swamps and the Shan Hills. It is the second largest lake in the country after the Indawgyi. The region is a large and flat valley, which is surrounded by the small mountain ranges Letmaunggwe, Thandaung et Udaung at the west and the highest Sindaung at the east, all part of the western border of the Shan Hills. The lake is feed by 17 rivers from the east and 12 rivers from the west. Kalaw and Indein/Balu enter the lake through large swampy deltas. An important part of the alluvial bassin of the Inle was one or several larger and deeper lakes before the end of the last Ice Age. The Thanlwin river is the only outlet, flowing south of the Inle. The lake is shallow (less than 5m of dept) and flat. It’s lenght is stable at 25-26km while the width decrease with time. Annandale measured 6.4 km in 1918 while now it is less than 5 km. The surface of the lake is aproximatly of 150km² with only 50km² of free water due to numerous floating islands. Some islands are natural, formed from entangled floating weeds but the people of the lake, the inthas, have domesticated this phenomenon and have created floating gardens where they cultivate tomatoes, eggplants and decorative flowers. The lake was once considered oligotrophic since it’s water come mostly from peat swamps. Once in the lake, after dissolving the limestone of it’s bottom the water become neutral and rich in minerals and carbon, but still nitrogen and phosphorus depleted and crystal clear. One fouth of the fishes found in the lake are endemic but with very similar cousins living all around Myanmar. In the lake’s environement, fishes have usually larger eyes and no barbels compared to species from the surounding area. The lake is also exeptionally rich in gastropods with dozens of present or subfossile species. Now the lake is eutrophic with turbid water. Yet crystal clear water can still be seen in some streams, pools and spings on it’s margins. I choose to recreate one of this sanctuaries.
Description of the underwater landscape of the biotope: The submerged landscape of the lake Inle itself is dominated by floating islands, herbarium of plants like Ceratophyllum demersum and small bushes of Nitella flexilis planted in clear, silty mud. The surounding area seems very diverse but with few to no pictures available on the internet. My tank was inspired by videos posted by Marli Mote Sate from springs close to lake Inle, where the vegetation is dominated by amphibious species like Rotala rotundifolia. The hardscape is made both of mineral elements like limestone blocks and wood, probably both living roots and dead trees. The substrate is similar to fine grey or reddish silt, patroled by crabs and snails. The water is cristal clear, mostly still, full of schools of small fishes.
Description of the parameters of the habitat: The temperature of the water is stable most of the year at 27-28°C with a big drop to 18-20°C in november and a smaller drop to 23-24 in april. Chemical parameters are chaotic due to the duality between the acidic peat water and the karstic nature of the Shan Hills. The conductivity can swing from 50 to 150 µS/cm and the pH from 6.5 to 9.
List of fishes and invertebrates occurring in the nature biotope: Fish:
Clarias cf. batrachus
Glossogobius cf. giuris
Puntius cf. sophore
Systomus cf. rubripinnis
Caridina cf. babaulti ‘Green’
Macrobrachium assamense assamense
List of plants found in the nature biotope: Adiantum edgeworthii
Cladium mariscus jamaicense
Cyperus sp. « Sha-pya »
Machaerina sp. « Sha-lone »
Threats to the ecology: The aquarium setup is chosen to give Sawbwa resplendens a lot of spawning media. They lay sticky eggs to the Nymphoides leaves wich are easy to cut and move to an incubation tank. This unique cypriniform is endemic to the lake Inle and is threatened by human activities and the introduction of alien species like the predatory Nile Tilapia. Siltification, floating island expansion, increasing turbidity and runaway growth of peat are also slowly chewing on the lake’s margins, while overfishing and the massive use of pesticides represent a direct impact on fish populations. One species, Systomus compressiformis, may have already disapeared. The snails from the genius Brotia are often exported world-wide for aquarists. Sadly most of them dont survive the shipment or die within months. This tank contain a collection of very young Brotia herculea wich mothers died in a fishstore shortly after giving birth. I hope to find the proper diet and care to ensure no more capture will be needed to sustain the hobby in future.
Sources of information:
La région du lac Inlé (Birmanie) dans la mondialisation: une région en transition (Martin Michalon, 2014)
Analysis of water pollution in freshwater Inle lake based on eutrophysation (Mar Lar Htwe, 2008)
The conservation of aquatic and wetland plants in the Indo-Burma region (In Allen et al. 2012)
An updated checklist of aquatic plants of Myanmar and Thailand (Yu Ito & A.S. Barfod, 2014)
Study on the formation of floating islands in the Inle Lake from botanical point of view (Khin Win Myint & Kyaw Win Maun 2001)
A dataset of fishes in and around Inle Lake, an ancient lake of Myanmar (Yuichi Kano et al. 2016)
The freshwater palaemonid prawns of Myanmar (Yixiong Cai & Peter K. L. Ng, 2002)
Freshwater shrimps of the genus Caridina from Myanmar (Yixiong Cai & Peter K. L. Ng, 2002)
The faune of Inle lake (Nelson Annandale, 1918)
Crustacea Decapoda of the Inle lake bassin (Stanley Kemp, 1918)
Further observations on the aquatic gastropods of the Inle lake watershed (Nelson Annandale, 1925)
A systematic revision of the southeast asian freshwater gastropod Brotia (Franck Köhler & Matthias Glaubrecht, 2006)
Racesina, a new generic name for a group of Asian lymnaeid snails (M.V. Vinarski & I.N. Bolotov, 2018)
Also private discussions with Werner Klotz