Ralph
01-10-2003, 11:35 AM
Rio Jatapu Biotope
an Interview with Oliver Lucanus
This is the first in a series of interviews of discus experts who have been to the Amazon. Each interview will focus on a specific area and will describe the environment in which the discus live. The principle intent is to provide a visual description for those people interested in creating a discus biotope in their aquariums. But the information provided will help all of us to better understand our discus and where they come from.
Our first expert is Oliver Lucanus. He is involved in more things than I can name but he is probably best know as the owner of Below Water (www.belowwater.com), a large tropical fish wholesale importer, located in Montreal, Canada. He is also an author, photographer, and is sponsoring The Red Island Damba Project, a conservation project to save Madagascar’s disappearing wildlife areas. He has written over 200 articles, is an associate editor for Tropical Fish Hobbyist Magazine, and has judged international discus shows. He also travels extensively (he is in Brasil right now on another trip) and conducts expeditions to the Amazon and Africa. And somehow he made time to do this interview.
Everything in parentheses is by me.
What area of the Amazon River Basin would you like to discuss?
My comments will refer to a clear water habitat along the upper Rio Jatapu (Located east of the Rio Negro, it is a tributary of the Rio Uatuma which enters the Amazon River from the north between Manaus and Nhamunda). Discus are typically a mixed water fish and there are few places where you can actually observe discus under water like you can in a clear water stream.
What kind of discus did you see on the Rio Jatapu?
The fish here are nearly all Royal Blue (http://www.belowwater.com/fish/wild-discus/index.html). The fish are larger and more powerful than in any other habitat that I have seen. The discus live in what is best described as a stream. The sides are about 6 ft deep at peak dry season. The center is shallow at about 1 foot. At this time of year you could swim against the current. The flood zone into the main river is a large lake several miles long, here the water is slower moving and there are no discus in the dry season.
Whenever someone talks about a discus biotope, driftwood is usually the first thing mentioned. Was there a lot of driftwood in that area?
Lots of wood. I have a picture here:
(http://www.belowwater.com/fish/brazil-2001/index.html)
What other types of fish have you seen living in close proximity to discus in that area?
The Rio Jatapu is the only habitat I have seen where discus are the dominant species in mass. They account for about 50% of the total number of fish.
Other fish here are:
Cichla spp. (Peacock Bass) 5%
Uaru amphicantoides & Heros spp (Severums) 10%
Crenicichla lenticulata, regani and others 10%
Characins - Leporinus , Prochilodus and Curimatiids 20%
Catfish - Ancistrus (Bristlenose Pleco), Doradids 5%
There are some electric eels but notably no stingrays or piranhas.
Tetras and Apistogramma and the like were not counted in my percentages
Did you see other animals and insects in proximity to discus in that area?
There are some snakes, a few frogs and lots of butterflies as anywhere in the Amazon. Mammals are rarely seen in South America. Notably there are no otters or dolphins here in the side arms.
The water is too soft for aquatic invertebrates like snails or shrimp – but there are lots of Tubifex type worms.
Did you see aquatic plants in proximity to the discus? Did you see floating plants in that discus area? We’ve all seen pictures of the floating Victoria Lily pads, are lily pads part of the discus environment? Are water reeds and other emergent plants in that discus area?
Here there are no water plants at all and I have never seen Victoriana in any discus habitat. There is hairgrass in the dry season along the edges of the Rio Jatapu.
The only plants I have seen in over 50 different habitats of discus is Nuphar spp (Lily pads) and Myriophyllum (Milfoil or Foxtail). I have never seen any Echinodorus (Swords) in discus habitats.
What did the water look like there?
The water parameters are pH 6, GH2, temp 29C at any depth, and the visibility is about 8 ft. The water is fast moving here.
Is algae commonly found in that area?
There is almost no algae. Considering the water parameters it would not be expected. A high flow rate also brushes away almost all detritus.
In that area, what does the stream bed look like? Is it sand, mud, silt and did you see any rocks? Is leaf litter commonly found in the area?
The stream bottom is a fine white sand. Behind larger downed trees there is some leaf litter and branches. There are NO rocks in this area.
There are books written on the inundation that takes place during the rainy season. But how does it affect the discus in that area?
Yes, the water level rises and the habitat gets very wide, the discus then have plenty of places to lay eggs and forage. The water movement also slows down.
All the pictures that I have seen of discus collecting seem to be on rivers, but I have heard that discus often occupy lakes (ox bows). Have you found discus in both areas and if so, are there differences other than water flow between the two?
They are extremes in terms of water flow. I have seen discus even among sharp edged rocks of the main rivers but in the Peruvian and western Brazilian Amazon the oxbow habitat is more typical. Most people travel only to the main river habitats and that is how it was assumed that all discus live in these conditions.
I really want to thank Oliver for taking the time to answer my questions, especially since he was in the middle of getting ready for his next trip. I also want to thank Al (brewmaster15) and John (DarkDiscus) for their help in making this possible.
an Interview with Oliver Lucanus
This is the first in a series of interviews of discus experts who have been to the Amazon. Each interview will focus on a specific area and will describe the environment in which the discus live. The principle intent is to provide a visual description for those people interested in creating a discus biotope in their aquariums. But the information provided will help all of us to better understand our discus and where they come from.
Our first expert is Oliver Lucanus. He is involved in more things than I can name but he is probably best know as the owner of Below Water (www.belowwater.com), a large tropical fish wholesale importer, located in Montreal, Canada. He is also an author, photographer, and is sponsoring The Red Island Damba Project, a conservation project to save Madagascar’s disappearing wildlife areas. He has written over 200 articles, is an associate editor for Tropical Fish Hobbyist Magazine, and has judged international discus shows. He also travels extensively (he is in Brasil right now on another trip) and conducts expeditions to the Amazon and Africa. And somehow he made time to do this interview.
Everything in parentheses is by me.
What area of the Amazon River Basin would you like to discuss?
My comments will refer to a clear water habitat along the upper Rio Jatapu (Located east of the Rio Negro, it is a tributary of the Rio Uatuma which enters the Amazon River from the north between Manaus and Nhamunda). Discus are typically a mixed water fish and there are few places where you can actually observe discus under water like you can in a clear water stream.
What kind of discus did you see on the Rio Jatapu?
The fish here are nearly all Royal Blue (http://www.belowwater.com/fish/wild-discus/index.html). The fish are larger and more powerful than in any other habitat that I have seen. The discus live in what is best described as a stream. The sides are about 6 ft deep at peak dry season. The center is shallow at about 1 foot. At this time of year you could swim against the current. The flood zone into the main river is a large lake several miles long, here the water is slower moving and there are no discus in the dry season.
Whenever someone talks about a discus biotope, driftwood is usually the first thing mentioned. Was there a lot of driftwood in that area?
Lots of wood. I have a picture here:
(http://www.belowwater.com/fish/brazil-2001/index.html)
What other types of fish have you seen living in close proximity to discus in that area?
The Rio Jatapu is the only habitat I have seen where discus are the dominant species in mass. They account for about 50% of the total number of fish.
Other fish here are:
Cichla spp. (Peacock Bass) 5%
Uaru amphicantoides & Heros spp (Severums) 10%
Crenicichla lenticulata, regani and others 10%
Characins - Leporinus , Prochilodus and Curimatiids 20%
Catfish - Ancistrus (Bristlenose Pleco), Doradids 5%
There are some electric eels but notably no stingrays or piranhas.
Tetras and Apistogramma and the like were not counted in my percentages
Did you see other animals and insects in proximity to discus in that area?
There are some snakes, a few frogs and lots of butterflies as anywhere in the Amazon. Mammals are rarely seen in South America. Notably there are no otters or dolphins here in the side arms.
The water is too soft for aquatic invertebrates like snails or shrimp – but there are lots of Tubifex type worms.
Did you see aquatic plants in proximity to the discus? Did you see floating plants in that discus area? We’ve all seen pictures of the floating Victoria Lily pads, are lily pads part of the discus environment? Are water reeds and other emergent plants in that discus area?
Here there are no water plants at all and I have never seen Victoriana in any discus habitat. There is hairgrass in the dry season along the edges of the Rio Jatapu.
The only plants I have seen in over 50 different habitats of discus is Nuphar spp (Lily pads) and Myriophyllum (Milfoil or Foxtail). I have never seen any Echinodorus (Swords) in discus habitats.
What did the water look like there?
The water parameters are pH 6, GH2, temp 29C at any depth, and the visibility is about 8 ft. The water is fast moving here.
Is algae commonly found in that area?
There is almost no algae. Considering the water parameters it would not be expected. A high flow rate also brushes away almost all detritus.
In that area, what does the stream bed look like? Is it sand, mud, silt and did you see any rocks? Is leaf litter commonly found in the area?
The stream bottom is a fine white sand. Behind larger downed trees there is some leaf litter and branches. There are NO rocks in this area.
There are books written on the inundation that takes place during the rainy season. But how does it affect the discus in that area?
Yes, the water level rises and the habitat gets very wide, the discus then have plenty of places to lay eggs and forage. The water movement also slows down.
All the pictures that I have seen of discus collecting seem to be on rivers, but I have heard that discus often occupy lakes (ox bows). Have you found discus in both areas and if so, are there differences other than water flow between the two?
They are extremes in terms of water flow. I have seen discus even among sharp edged rocks of the main rivers but in the Peruvian and western Brazilian Amazon the oxbow habitat is more typical. Most people travel only to the main river habitats and that is how it was assumed that all discus live in these conditions.
I really want to thank Oliver for taking the time to answer my questions, especially since he was in the middle of getting ready for his next trip. I also want to thank Al (brewmaster15) and John (DarkDiscus) for their help in making this possible.