Central American Fast-Moving Stream, Atlantic Slope Biotope Aquarium Setup


A biotope aquaria is an aquarium that is set-up to simulate a natural habitat. The fish, plants, water chemistry, and furnishings are similar to those that can be found in a specific natural setting.

Central American Fast-Moving Stream, Atlantic Slope
The Rio Zacate and the Rio Corinto, Honduras

In 2004 I visited the Pico Bonito National Park on the Atlantic slope of Honduras. Parque Nacional Pico Bonito is the largest protected area in Honduras after the Rio Platano Biosphere Reserve. Spanning over 7800 feet (2400 meters) in elevation and capped by the 7900-foot-high (2435 m) Pico Bonito, the park ranges from humid tropical broadleaf forest to high cloud forests.

The park is the source for at least 22 rivers -- some which cascade down from the highlands in a series of spectacular waterfalls. The following describes a small stream at an elevation of 150-600 feet (50-180 m). These streams generally flow year round but fluctuate wildly with rain. Following rain in the highlands, rivers can rise dramatically in just a couple of hours -- from picturesque bluish-clear streams to boiling whitewater rapids.

The substrate is typically boulders and rocks. In pools there is gravel or sand. Tree roots grow down the bank into the river creating ideal hiding places for fish -- especially in deeper pools. Fallen trees trap debruis and form further shelter for larger fish. Streamside vegetation is often submerged when water levels rise and there are aquatic plants in some of the pools.

Unfortunately the conditions made it impossible for me to take underwater pictures. I came ready with the underwater camera, but in 6 days it never stopped raining in the highlands and water flows kept these streams too dangerous for much hands-on exploration [actually had I known it would have been my only opportunity, I could have gotten in the water my first morning before the rains]. I also lost my water testing materials before ever having the opportunity to use them so I don't have any readings for these rivers.

Since these streams are so variable you have lots of biotope options. You could opt for the 1) swift-moving rapid section of the creek, 2) a pool bordered by roots from a rainforest tree and streamside vegetation, 3) the shaded zone under a fallen tree, or 4) a small bowl-shaped pool created by a side flow of the creek.

pH: 7.0-8.0, 5-14 dH, 75-86 F (24-30 C)
(Test kit lost before readings could be taken)

1) A biotope modeled after the rapid section of the stream may be a little on the boring side as fewer fish and even less vegetation are found in this part of the habitat those described below. For the adventurous, direct filter outflows so as the create a strong current and provide plenty of aeration. Use large rocks and gravel as a substrate. If you want plants you can sneak in a couple of current-tolerant Vallisneria. For fish, stick with ....

2) Use roots and or aquarium-suitable wood in one corner of the tank. Plant densely around the sides of the aquarium and scatter some large rocks. The substrate should be sand or fine gravel. Allow algae to grow on rock surfaces. Water current can be minimal to moderate.

3) Use aquarium-suitable wood to create a "shelf" and other hiding places. Use a sand or fine gravel substrate. Add a few floating plants and scattered Vallisneria. Water current should be minimal.

4) To recreate this biotope you can use a 10-20 gallon aquarium. Ideally the substrate would be sand with pieces of flat rock lused to create "walls" at the rear and on the sides of the tank. Let algae grow on the rocks and place a single plant in the corner of the tank. Keep water current to a minimum.

Sword plants, Heteranthera, Ceratophyllum, Vallisneria, Cabomba
See for yourself: Rio Zacate vegetation pictures

Long fin Cichlid - Amphilophus longimanus (known locally as Carataca or Machaca). "Abounds more in stagnant waters although also found in strong current. Browse on soft bottoms picking up aquatic insects" [quote: Fishbase.org] [Picture]
Pastel cichlid - Amphilophus alfari. "Inhabits all sections of the river from the fast flowing upper sections to the slower moving lower reaches. Collected between 2 and 1150 m elevation. Prefers sand or mud substrata where it sifts for aquatic insects" [Fishbase.org] [Picture]
Convict cichlid - Archocentrus nigrofasciatus (known locally as Congo) "Inhabits flowing water from small creeks and streams to the shallows of large and fast flowing rivers. Prefers rocky habitats and finds sanctuary in the various cracks and crevices provided by this type of environment, or among roots and debris. Occurs in warm pools of springs and their effluents. Feeds on worms, crustaceans, insects, fish and plant matter." [quote: Fishbase.org]
Ariidae catfish find their way upstream from brackish water estuaries.
Schooling Fish
Some unidentified minnow-like fish. At least one characin is found in somewhat similar habitats in Honduras:
Hyphessobrycon tortuguerae "Inhabits backwaters and creeks with low or moderate current velocity. Found between elevations of 0 to 50 m, insectivore" [quote: Fishbase.org]
Here are some other species found in and around this habitat:
Alfaro huberi "Inhabits clear, fast-flowing waters" [quote: Fishbase.org] [Picture]
River goby - Awaous banana "Inhabits clear streams and rivers over sand and gravel, but also found in turbid waters with muddy bottoms. Prefers clear flowing, well oxygenated streams. Feeds mainly on filamentous algae" [quote: Fishbase.org] [Picture]
Gobiesox nudus "Inhabits rivers and creeks between 25 and 580 m elevation, in currents of high velocity and feeds on fish, fish scales and aquatic insects (Ref. 36880). Occurs solitarily in streams" [quote: Fishbase.org]
Merry widow livebearer - Phallichthys amates "Occurs mainly in stagnant waters, creeks and river shorelines, over soft bottoms... Feeds on ooze, detritus, diatoms and occasionally on filamentous algae and aquatic insects" [quote: Fishbase.org] [Photo]
Dogtooth rivulus - Rivulus tenuis
Also saw some darter-like fish which I couldn't identify. Many of the species listed above are not readily available in the hobby. I suggest substituting similar species in their place. See Fishbase - Honduras listing or a broader broader look at Central American Fish

Rio Zacate, Honduras
Rio Corinto, Honduras