San Juan, Pacific coast of Nicaragua Lake

40th place in Biotope Aquarium Design Contest 2019

Turkey. Yiğitcan Uslu

Volume: 270 L
Dimensions: 100x60x45 cm
List of fishes: Amatitlania nigrofasciatum.
List of plants: Lemna minor , Pistia stratiotes, vallisneria sp.
Description of decorations: – I only used natural ingredients. There’s fine sand
On the floor and gravel, rock, Oak-tree leaves and pieces.
Description of equipment: Tetra EX 1200+ ,Jbl protemp S300, 2pcs 20 watt 6500 kelvin LED light.
Water parameters: Temperature is 27°C, pH:7.5 gH: >14
Additional info: 30% water change per week. and cleaning the filter once every 8 months.


Description of the area surrounding the biotope: Lake Nicaragua; The area is 8.029 km2, the length is 164 km, the width is 72 km, the deepest point is 70 meters, It is 32 kilometers above sea level. The region between Central America and the USA and Peru is the largest freshwater lake. Rivas Cascade’le separated from the Pacific Ocean lake, the Tipatapa River discharges excess water. With a little foot on the northwest end.
The San Juan River, which flows from the south to the Caribbean Sea, forms the eastern part of the Nicaragua-Costa Rica border.

Description of the underwater landscape of the biotope: The bottom has whitish sand and some gravel ,along the edge rocks. Driftwood is found in this habitat.There are some swamp plants like Echinodorus sp. Which grows out of the water and can be found along the lake or river bank,also Mayaca fluviatilis and some floating plants ( e.g. najas guadalupensis,Pistia stratiodes ,Salvinia auriculata)submerse only Vallisneria americana.)

Description of the parameters of the habitat: Measurements made at different points of Lake Nicaragua
The temperature ranges between 24-30 ° C and pH 7-9. pH is particularly high Due to high photosynthesis on the surface and close to the shore. As depths and inclusions progress, Level down to 7.5. Hardness is moderate. Chemical water parameters: pH 5,6, conductivity 200 / cm, temperature up to 29 ° C

List of fishes and invertebrates occurring in the nature biotope: Lake Nicaragua does not only host Cichlids.
The most famous member of the sword tail and mole, which is very common in our country, hosts the most common live births.
Also living in large groups on the shallow shores of this lake. Ghost shrimp and cambarellus freshwater crayfish
His family are the most typical invertebrates of this lake. Rhamdia catfish and crocodile fish are predators of the lake.
Cichlids in the aquarium hobby are rainbow, zebra, midas, macav, dovii, jaguar, black belt. Amphilophus is the only endemic life. Although it hosts vast cichlids such as Amphilophus labiatus (red devil), amatitlania, archocentrus, cryptoheros, excichlasoma, Parachromis, Vieja and Paratheraps families. Hypsophrys nicaraguensis, Archocentrus multispinosa, Gambusia affinis, Amatitlania nigrofasciata, Achirus mazatlanus, Acromycter atlanticus, Gonostomus monticola, Alfaro cultratus, Alfaro huberi, Amatitlania nigrofasciata, Amatitlania septemfasciata, Amatitlania siquia, Amphilophus amarillo, Amphilophus astorquii, Amphilophus chancho,
Amphilophus citrinellus, Amphilophus flaveolus, Amphilophus globosus, Amphilophus labiatus, Amphilophus sagitta, Amphilophus supercilius, Amphilophus tolteca, Amphilophus viridis, Amphilophus xiloaensis, Amphilophus zaliosus
Anchoa parva, Anguilla rostrata, Archocentrus centrarchus, Ariopsis assimilis, Ariopsis seemanni, Astyanax aeneus, Astyanax cocibolca, Astyanax nasutus, Astyanax nicaraguensis, Atherinella argentina, Atherinella hubbsi, Atherinella jiloaensis, Atherinella sardina, Atractosteus tropicus, Awaous banana, Belonesox belizanus, Brachyrhaphis holdridgei, Bramocharax bransfordii, Brycon costaricensis, Brycon guatemalensis, Carcharhinus leucas, Carlana eigenmanni, Cathorops fuerthii, Cathorops steindachneri, Centropomus ensiferus, Centropomus nigrescens, Centropomus parallelus, Centropomus pectinatus, Citharichthys gilberti, Cribroheros alfari, Cribroheros longimanus, Cribroheros rostratus, Cryptoheros spilurus, Ctenogobius claytonii, Cynodonichthys isthmensis, Cyprinus carpio, Dormitator latifron, Dorosoma chavesi, Eleotris picta, Eleotris pisonis, Erotelis smaragdus, Eucinostomus argenteus, Eucinostomus currani, Eucinostomus gracilis, Eugerres plumieri, Gambusia nicaraguensis, Gerres cinereus, Gobioides peruanus, Gobiomorus dormitory, Gobiomorus maculatus, Hemieleotris latifasciata, Herotilapia multispinosa, Hypsophrys nematopus, Hypsophrys nicaraguensis, Joturus pichardi, Kuhlia mugil, Lile stolifera, Mayaheros urophthalmus, Microphis lineatus, Mugil cephalus,
Mugil curema, Oligoplit palometa, Oncorhynchus tshawytscha, Oreochromis aureus, Oreochromis mossambicus, Oreochromis niloticus, Oxyzygonectes dovii, Parachromis dovii, Parachromis friedrichsthalii, Parachromis loisellei, Parachromis managuensis, Phallichthys amates, Phallichthys tico, Poecilia mexicana, Pomadasys ladies, Pomadasys crocro, Priapichthys panamensis, Pseudophallus mindii, Pseudophallus starksii, Rhamdia guatemalensis, Rhamdia laticauda, Rhamdia nicaraguensis, Rhamdia quelen, Roeboides bouchellei, Sicydium salvini, Strongylura exilis, Strongylura marina, Synbranchus marmoratus, Tomocichla tuba, Vieja maculicauda, Xenophallus umbratilis. species in this basin.

List of plants found in the nature biotope: The following plant species were found in Nicaragua lake. -Echinodorus sp, Mayaca fluviatilis, najas guadalupensis, Salvinia auriculata, Lemna minor.

Threats to the ecology: Despite the enormous ecosystem in and around the lake, Despite being an important potential source for potable water and despite its large attraction for ecological and sustainable tourism Lake Nicaragua does face problems of contamination that could become much worse in the middle-long term (and some in the short term as well) if necessary steps to prevent so are not taken. Even though this situation Has been publicly acknowledged by institutions, organizations, experts, and citizens there is not yet a national plan that addresses
Conservation of this beautiful lake. There are three principal contamination threats and although at this time all three of them can be controlled or eliminated It does require effort and commitment by all parties and authorities involved, as well as support of the population. The main problem and source of contamination for Lake Nicaragua are related to the discharge of wastewater that comes From the urban zones at the shores of the lake. In spite of the clear contamination That results from this practice, large cities as Granada, Rivas and Juigalpa and many small towns still lead their sewage from residential areas
But even from industrial zones to the lake (either directly or through a river that terminates in the lake). Consequently, coastal areas close to these urban centers have to deal with the waste that is not biodegradable Which surfaces in front of the settlements. The second largest problem comes from the agricultural industry in the coastal areas. The fertile soil next to the lake provides a great site for cattle farming and plantations.
In the departments of Chontales, Boaco and Rivas there are many places where people farm without protecting the lake whatsoever, leading to contamination with enormous quantities of fertilizers ending up in the water. Another even more important impact is caused by the nearby agricultural haciendas that contaminate the rivers Flowing into the lake by the unprotected usage of chemicals at their plantations.
This problem is mostly visible at the southern side of the lake on Nicaraguan territory But also on Costa Rican soil (as these rivers also terminate in Lake Nicaragua). The third problem is a controversial issue related to the recent introduction of new fish species inside floating cages in the lake. Although the foreign firm that develops this project obtained the governmental permits And even though the fish breeding has already started, there has been strong disapproval by ecologists, Social organizations and communities ever since the beginning. The problem, the critics point out, is that the huge quantity of Tilapia fish Generates large waste quantities that the lake has to adsorb. The biologists also warn that the Tilapia might bring diseases that the endemic fish are not prepared for. What is currently necessary is implementation of measures by the national authorities to face the aforementioned Problems and to prevent other problems that might threaten the lake in the future. Several organizations are already promoting the Idea of preserving and protecting Lake Nicaragua, but so far these issues lack importance on the national agenda. In addition to the large tourism potential, the lake also has a potential to function as source for potable water for national use and export.
The Centrum of Investigations of the Aquatic Resources (Centro de Investigación de los Recursos Acuáticos), CIRA-UNAN, indicates That the lake discharges 478 cubic meters of water per second through the San Juan River (registered by the Nicaraguan Institute of Territorial Studies – INETER). Per day this amounts to 41.3 million cubic meters. This water can become an important renewable source of income if commercialized. The CIRA therefore warns not to let companies and private producers contaminate the lake. At this moment the UNESCO has already received a petition from the Nicaraguan government to declare Lake Nicaragua World Heritage. The authorities and the hundreds of communities set around the lake have expressed their enthusiasm and hopefully the UNESCO will grant the request. But in order to protect the lake the national and local government, as well as every Nicaraguan Citizen and foreigner that wants to enjoy this lake, should become involved and act in order to preserve this natural treasure!

Sources of information:

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