Rahtawu Kudus River in the dry season of Central Java, Indonesia

50th place in Biotope Aquarium Design Contest 2019

Indonesia. Nasrul Karim

Volume: 160 L
Dimensions: 100×40×40 cm
List of fishes: rasbora argyrotenia, barbodes binotatus, nemachilus fasciatus, crustacea, poecilia reticulata, channa gachua, sulchospira testudinaria, parathelphusa convexa
List of plants: murdannia sp, vesicularia dubyana, cyperus rotundus, ipomoea aquatica forsk, colocasia esculenta, microsorum pteropus, floscopa, ceratophillum demersum
Description of decorations: the material used in this aquarium is collected directly from the margins of the rahtawu river such as rocks, sand, wood, plants, fish, along with the water source. Brown sand is formed from rock rock eroded by heavy water currents. the purpose of collecting raw materialsto make a copy of the underwater river Rahtawu ecosystem to resemble the design and ecosystem of the river
Description of equipment: water filtration using DIY amara filter canister 1500L / h with biological media. assisted by amara 1000L / h for the effects of heavy current. while the lighting used is 70 watts led 6500k smd strip
Water parameters: odorless aquarium water with turbidity level of 1.71NTU, temperature 23 ° c, DHL 290, TDS 185 and PH 5.7. the water is slightly acidic because all the components in the aquarium are taken from the riverbank
Additional info: water replacement 2 weeks 40% use the same water source as the river, the room temperature can be low because of the hillside area .


Description of the area surrounding the biotope: Rahtawu River is upstream from the Gelis River. and empties into the river wedung demak. The rahtawu river is located in a green valley surrounded by hills with an altitude of 1,627mpl. the river area is the northwest part of Kudus Regency, Central Java, Indonesia. located in the coordinates -6.6630131, 110,858,643. the water flowing into the rahtawu river comes from the accumulation of water deposits produced from the roots of trees in muria mountain slope forests that pass rocky slopes and gather together in the rahtawu river valley.
Rahtawu river flows between the cliff slopes formed by hot lava flows from Mount Muria thousands of years ago. forming very natural rock slopes. making the winding river winding and the cave formed by rock due to erosion from the heavy flow of water. big rock and solots of small stone relics of mountain muria are active in the past …

Description of the underwater landscape of the biotope: the length of the rahtawu river is approximately 25 kilometers, with a water depth of 30 — 160cm in its basin during the dry season. with the shape of the mountain slope region causing heavy water currents. a lot of weathered wood that sinks and drifts away. various types of plants and half waterfloat on the banks of the river. and there are several types of algae that grow on rocks due to exposure to sunlight and the large amount of water flow ..

Description of the parameters of the habitat: the parameters of the natural habitat are slightly acidic. with ph 4.79 it is caused by the forest area through which water reaches the river. the water temperature during the dry season during the day reaches 23 ° c and 14 ° c at night

List of fishes and invertebrates occurring in the nature biotope: in the upstream waters this river has a wide variety of species during the dry season such as rasbora argyrotaenia with large amounts of swimming against the flow. whereas barbodes binotatus eats moss that grows on rocks. nemachilus fasciatus, crustachea, channa gachua, parathelphusa convexahiding between rocks and sometimes revealing himself. while poecilia reticulata swims on the banks of the river choosing calm currents. there are some senegalensis ischnura larvae hiding in the sand ready to wait for their prey to indicate that the water in their habitat is clean and decent adrink other living things. many testudinaria sorcospes attached to rocks add to their wild effects

List of plants found in the nature biotope: the riverside plants are ipomoea aquatica forsk, colocasia esculenta, cyperus rotundus, murdannia, marsilea, lemna sp, floscopa, eichhornia crassipes, ceratophillum demersum which can be found along the river flow. and many vesicularia dubyana, selaginela willdenowii ,microsorum pteropus, grows on the slopes of a river that is surrounded by water from the roots of a large tree on a cliff ..

Threats to the ecology: I made the biotope aim to tell the community that the habitat under the river is very good. It is very regrettable that until it breaks, recently the surrounding community often catches fish with dangerous tools such as stun and poison. which results inreduced biota in the river. for example, the late homaloptera fish are very rare and almost extinct. Homaloptera fish, including fish protected number 1 in Indonesia, used to have many of these fish attached to river rocks. this is due to human activities that are less environmentally friendly,
hopefully with the example of a small natural imitation the community can maintain this beautiful river again

Sources of information:

this written information is based on the personal surf that was uploaded on https://mobile.facebook.com/story.php?story_fbid=2356641631070563&id=100001742470945&_ft_=mf_story_key.1205195472984691%3Atop_level_post_id.1205195472984691%3Atl_objid.1205195472984691%3Acontent_owner_id_new.663503630487214%3Aoriginal_content_id.2356641631070563%3Aoriginal_content_owner_id.100001742470945%3Athrowback_story_fbid.1205195472984691%3Apage_id.663503630487214%3Aphoto_id.2356606884407371%3Astory_location.4%3Aattached_story_attachment_style.video_inline%3Apage_insights.%7B%22663503630487214%22%3A%7B%22role%22%3A1%2C%22page_id%22%3A663503630487214%2C%22post_context%22%3A%7B%22story_fbid%22%3A1205195472984691%2C%22story_fbids%22%3A%5B1205195472984691%5D%2C%22publish_time%22%3A1562151326%2C%22story_name%22%3A%22EntStatusCreationStory%22%2C%22object_fbtype%22%3A266%7D%2C%22actor_id%22%3A663503630487214%2C%22psn%22%3A%22EntStatusCreationStory%22%2C%22sl%22%3A4%2C%22dm%22%3A%7B%22isShare%22%3A1%2C%22originalPostOwnerID%22%3A2356641631070563%7D%2C%22targets%22%3A%5B%7B%22page_id%22%3A663503630487214%2C%22actor_id%22%3A663503630487214%2C%22role%22%3A1%2C%22post_id%22%3A1205195472984691%2C%22share_id%22%3A0%7D%5D%7D%7D%3Athid.663503630487214%3A306061129499414%3A2%3A0%3A1564642799%3A-1295888009866603910&__tn__=%2AsH-R
and from various sources

Comments of the members of the jury of Biotope Aquarium Design Contest 2019