Denison Barb

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stanleo

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Are Denison barbs (Barbus deninoii) schooling fish? Do they need to kept more than one like other barbs?
 
Yes, they're schooling fish so should be kept in a small group.
 
They also grow to be 5 inches + and are active swimmers and thus need at least a 3 ft long tank at least. They are very pretty fish which will harm nothing in a tank.
 
A group of 10+, in a 5-foot tank that changes temperature through the seasons (~15C winter season through to ~25C summer season; spring/autumn ~20C) and lots of water movement for high oxygen levels in a sight to behold.
 
A very misunderstood fish in the hobby, they are not "tropical" fish.
 
I have kept mine in tropical temps for years and they seem to do fine. 25C is a tropical temperature
smile.png
Mine are in warmer.
 
This species does best in larger groups, meaning eight or more.  There are reports of aggressive behaviour and this is likely due to the group being too small.  As the fish attains six inches, this means a 5-foot tank is best, though a 4-foot 90g can suffice.  The temperature range is usually considered to be 15-25C/59-77F, and given the high oxygen requirement, I would suggest avoiding the upper end of this range.  The species is endemic to SW India where it inhabits fast-flowing streams and rivers in the hills, occurring in shoals in rocky pools with thick marginal vegetation.  The habitat water temperature averages the afore-mentioned range.
 
This is  a fish that is often misunderstood as someone mentioned.  A forest stream tank with a good flow from the filter would make a nice display if one wants to see the fish at its best.
 
Byron.
 
Its nice to see you posting here Byron, your input and experience should benefit a lot of folks. I sure hope you decide to stay around.
 
Current is nowhere near as important as well oxygenated water. I would offer the following from seriouslyfish.com
 Though torrent-like conditions are unnecessary it also does best if there is a high proportion of dissolved oxygen and moderate water movement, and weekly water changes of 30-50% tank volume should be considered routine.
from http://www.seriouslyfish.com/species/puntius-denisonii/
 
I am far from an expert on these fish as I have only kept them for about a decade. I am on my second group though. I have found this to be the case with many fish from fast flowing waters, good oxygenation is essential.
 
By way of anecdote, I now have them in a tank with clown loaches of decent size. I had my old denisonii group in there for their last few years and, as old age took them, I decided to replace them. I bought 4 smaller ones, 2 or so inches, and after they cleared quarantine in they went with the lone surviving 6 inch one. Things seemed fine for about two weeks and then suddenly all but the large one was gone without a trace. My best guess is they ended up inside the loaches. I am also not sure why, but in my tanks these fish develop amazing colors despite my water being softer and warmer than might be ideal. They are one of those fish that after seeing a picture I had to have.
 
This is Rudolph the red-nosed reinfish-
i-wJt97rS-S.jpg

 
When they mature they get an amazing green coloration to their scales which are outlined with a lighter thin line. You have to look at them from above to appreciate it.
 
Thank you for the kind words.  I'm looking for a new home, as it were.
 
I hope I didn't imply a torrent, sorry if that came across.  I was thinking along the lines of your citation; Matt (at SF) and I are always on the same page.  Water movement is the best way of ensuring well-oxygenated water, but it doesn't take a torrent to achieve this.
 
I would watch the temperature.  With any fish, the higher the temperature the harder the fish has to work just to carry out its everyday functions.  Over time this does wear the fish down, sort of like "burning out."  At lower temperatures, the fish's physiological processes will require less energy, which means more energy can go into maintaining the immune system, spawning, "having fun," etc.  And of course, the warmer the water the less oxygen available to the fish so this is part of the extra work.
 
Byron.
 
I've seen the anti-social personality of Redline Torpedo Barbs first-hand, I started with 3 and there was a dramatic change when I added another 3 to their QT a few days later.
 
Moving them between tanks is a loaded game of "Russian roulette," they are unbelievably sensitive to water chemistry and temperature changes! The only times I have not lost any following a move is when they have had ~3 hours of slow drip acclimitisation, when I adopted 5 in early 2013 I felt the need to speed up acclimitising to ~45mins and I sadly lost three of the five within a few days.
 
Their expected lifespan is ~8 years, but numerous anecdotal reports scattered over the internet talk of many only managing 5 years at best, with a common factor being a tank temperature of ~25C all year round, rather than letting their metabolic rate roughly half by having a "winter period" of ~15C.
 
Odd, I have moved mine at will and never lost one. My standard acclimation procedure for almost all fish is float the bag for temp 15 minutes and then into the tank. Since 2004 I have had about 10 of these fish in basically two batches. 3 new small ones became lunch for clown loaches after about 2 weeks and I had to replace them and let them grow out in another tank. I still have 4 today.
 
Nobody. can you please link me to the source for their lifespan, I would like to read more on this topic. I have found other information which contradicts yours both in terms of their sensitivity and their life span. You can see what I have read here http://freshaquarium.about.com/od/barbs/p/Denison-Barb-Puntius-Denisonii.htm I have also read some of the information from the Indian aquarist named Madan Subramanian.
 
Unfortunately this fish was so over collected and that combined with habitat loss and ended them up on the IUCN redlist- they are now considered endangered.
 
Lastly bear this in mind if you keep them:
 
This fish resembles the Siamese algae eater in shape but is far more colourful, with beautiful red and yellow stripes on its body and fins. It is in fact a barb, and is omnivorous.  It likes to swim in groups and is peaceful and non-territorial, and grows to about 16cm.  It is a jumper and should be in a covered tank. One of my Indian friends once had one jump five feet straight up out of a bucket - he caught it at eye level!
from http://www.aquarticles.com/articles/people/norfolk_madansubramanian.html
 
A few years ago I authored over 250 fish profiles for another site, and in my research on this species, Sahyadria denisonii as it is now classified, I found eight years was the average lifespan cited.  This varies from five to eight, with even ten mentioned.
 
Lifespan in the aquarium is frequently determined by the environmental conditions.  This is what I was hinting at previously, with the temperature and water flow.  Many fish will seem to be fine for whatever space of time, but not achieve their normal expected lifespan.  Often this is simply the result of the "wear and tear" on the fish from not being kept in its preferred environment.  The GH of the water is a major player in this, pH rather less provided it is not too far off, with temperature, the aquascape, filter flow, tank size, water changes, foods and tank companions all contributing factors to how long the fish lives.
 
I would suggest that the common five year lifespan for a fish that is expected to live longer is perhaps due to their being kept in less than favourable conditions.  One frequently hears that fish can adapt to different conditions, and commercially-raised fish will be fine in this or that, etc.  But such adaptation is primarily surmise or assumption and not always adequately documented as scientific fact.  I am reminded of a comment from Dr. Paul Loiselle in an article he wrote on providing a proper environment for fish:  "It is inhumane to deprive any animal of an element it regards as critical to its well-being, and totally naive to expect normal behavior in its absence."
 
Now, before some start jumping on me, let me say that I certainly acknowledge some degree of adaptability in many species, though less in others.  And the artificial environment we provide in an aquarium, no matter how "authentic" we may be, is always going to fall short of the natural environment.  But nonetheless, I believe there is scientific evidence that such adaptability has defined limits.  If a species has evolved over thousands of years to function at its best in a specific environment, why should we expect to change this overnight (in relative terms)?  Should we even attempt to do so?  Food for thought.
 
Byron.
 
This is a topic I have wondered about for some time. What I would like to know is how such lifespan figures are worked out. For example, we know that plecos, loaches and koi all live a long time, but how is this translated into a specific number of years? Above, Byron quoted 3 potential numbers for the denisonii lifespan which were 5, 8 and possibly 10 years. That is a pretty wide range. Its like my saying you have a chance of living to somewhere between the age of 40 and 80.
 
The fact is that a species in the wild does actually have an average lifespan, it is determining what that may be is where I see the problem. It seems for many fish the estimate of lifespan is just that, an estimate.
 
And when it comes to tanks the whole equation changes. In the wild some of a fish population will succumb to predation, in a tank the predators can be left out. In the wild food availability is variable, in a tank it can be kept at the most nutritional level. In the wild the only defense a fish has against disease and parasites are the natural ones, in a tank we can treat these things with meds. And then consider reproduction. In the wild one of the most common reproductive strategies is to produce many eggs/ fry and have a few survive. But in a tank the same spawn can be cared for so most of the offspring make it.
 
Of course the other side of this coin is that other factors can work in an opposite fashion. First and foremost, the fish are dependent on the actions of the fish keeper. Bad practices can create conditions in a tank that are harmful or deadly to a fish and which would never be encountered in the wild. The wrong TDS, pH, diet etc. can all be causes of a shorter lifespan. However, I believe that in a properly set up tank which is given the proper care, fish should have a longer average lifespan than they do in the wild. Even if some of the parameters may be a bit "out of range."
 
While some of this may be from adaptability, I think more of it is due to the other potential life extending factors mentioned above. The one thing I firmly believe is that no two tanks are exactly the same in terms of all the parameters. And if this is the case, trying to draw conclusions about tank lifespans on average becomes very difficult. We see this clearly in this thread simply by comparing my experiences to Nobody's in terms of the denisonii.
 
For most fish keepers, giving denisonii a winter is not feasible. My house stays between 69 and 78 F all year round and averages about 71, in C that is 20 - 25.5 and average of 21.6. In order to give my fish a "winter" would require a chiller and that is not in the cards.
 
Some very good and valid additional points there, absolutely.  Your temperature comments remind me of a related issue, namely day/night temperatures.  Tropical watercourses do not remain constant, though a deeper lake would obviously have less fluctuation than a shallow stream or pond.  And of course fish are able to move higher or lower to some degree, depending upon the depth.  It has been suggested that we should have two heaters in an aquarium, one set higher for daylight, and the other lower for night, and have them on timers.  Another option is to time the heater to simply go off at night, and rely on room temperature.  On Seriously Fish a while back, one very experienced aquarist documented having no heaters at all.  Obviously, this is somewhat governed by the ambient room temperature, since it certainly is possible to seriously impact and even kill fish with too low a temperature.
 
Even with a heater programmed for the same temperature 24/7, there will be temperature variables within the tank, large or small.  When I am doing water changes, it still surprises me at how much cooler the water down close to the substrate is, and this is before I begin.  I always refill with slightly cooler water, so naturally would expect some variance afterwards.  But even in my 10g the water is cooler above the substrate and warmer at the surface.  This does of course replicate water habitats in nature.  And while tank lights undoubtedly contribute somewhat to this, there is still the thermal layers in any body of water.
 
Byron.
 
Well a lot of that variance is due to the lid and the lighting in many cases. the lid prevents heat from escaping as efficiently and the lighting warms the water surface. Moreover people discount the heating effect of filters, pumps, powerheads and even air. If you have an airpump running in a 78 F fishroom, you are pushing 78 degree air through the water. The people who have it easy in terms of day night are those who heat tanks in a fish room via ambient temperature.
 
I have one small  heaterless tank, a 5.5 gal. which is about 6 ft. up a wall on a shelf. The room is warm enough year round to keep this tank in the 70s F.
 

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