Denison / Red-line Torpedo Barb

Native Location

Originally from parts of western India. It’s been collected from the rivers Chaliar, Chalakkudipuzha and Kallada, the wildlife sanctuaries of Aralam and Periyar and in Kallada, Mundakayam and Travancore. Most of the ones seen in the trade today originate from the Khozikhode (“Calicut” in English) province of Kerala.  It lives in fast flowing highly-oxygenated rivers and loves to swim against the flow in tanks with high flow from powerheads.

The torpedo barb grows quite large and is a very fast swimmer it likes lots of space to move and feels most at home in shoals of its own kind.  Because of this we recommend at least a 4 foot tank for keeping them in with a volume of at least 250 Litres.

Given its natural habitat it’s best kept in a set-up dedicated to the replication of a flowing stream. Use a sand or gravel substrate, and scatter some smooth, water-worn rocks of varying sizes around the tank. An external canister or internal power filter with the outlet placed at the water surface aiming down the length of the tank would provide the desired high levels of oxygenation and flow. An additional powerhead could also be used if you wish or a rivertank manifold could be installed.

Looking after your Torpedo Barb

The tank can be further furnished with driftwood branches and aquatic plants for aesthetic value although the vast majority of plant species will fail to thrive in such turbulent conditions. Possibilities include hardy species such as Java fern, Bolbitis or Anubias species which can be grown attached to the decor.

Alternatively it can look superb in a heavily planted setup, decorated with pieces of bogwood, twisted roots and a layer of surface vegetation. It tends to lose a lot of its colour in immature or sparsely-decorated tanks. A tightly-fitting cover is also important, as this fish is an accomplished jumper. Particular attention must also be paid to water quality, as the hill streams which the species inhabits in nature are typically very low in organic pollutants. A stringent maintenance regime is therefore needed to keep it in top condition.

Water Conditions

Temperature: Prefers slightly cool conditions. A temperature range of 59 – 77°F/15 – 25°C has been recorded in its natural waters.

pH: 6.8 – 7.8

Hardness: 5 – 25°H


Feeds mainly on insects and other invertebrates in nature although some vegetable matter (such as algae) is also taken. In the aquarium it’s easily fed and will greedily accept just about anything offered. For the best condition and colours offer regular meals of small live and frozen foods such as bloodworm, Daphnia and Artemia along with dried flakes and granules. It’s said that the species‘ colours can be intensified by feeding a diet rich in carotenoids such as astaxanthin.


Relatively peaceful but best kept with other rheophilic Asian species such as Danio, Devario, Barilius, Garra and balitorine loaches. This would make for a very interesting biotope-style community. That said provided its oxygen and temperature requirements can be met it can be mixed with most peaceful fish too large to be considered food.

Reports that the species is aggressive may stem from the fact that due to its high price often only one or two specimens are purchased. It’s a schooling species by nature and really should be kept in a group of at least 8-10 specimens. Maintaining it in decent numbers will not only make the fish less prone to bouts of skittishness but will result in a more effective, natural looking display. Any aggressive behaviour will normally also be contained as the fish concentrate on maintaining their hierarchical position within the group. A second species occasionally imported under the same name (see ‘notes’) is known to be more belligerent than P. denisonii so it’s possible that misidentification may also be partly responsible.


Can be tricky to sex correctly but sexually mature females tend to be more robust and rounder bellied than the noticeably slimmer males.

Very little information from the hobby exists although the species is definitely being bred on a commercial basis, presumably via the introduction of hormones.

In terms of hobbyist success at least one report of ‘accidental’ spawning exists where a couple of fry were discovered hiding among plants during tank maintenance. A more official report was published in the German magazine Aqualog in 2005. In this case the fish spawned in a group of 15 adults in soft, acidic water (gH 2-3/pH 5.7), depositing their eggs in a clump of Java moss. Apparently several of the participants underwent a change in colour prior to the event the dorsal surface turning blue. The spawning appeared to be triggered by a gradual lowering of the pH in the tank via the addition of some pieces of bogwood.

More recently Chester Zoo Aquarium in England have reported successful breeding. This occured accidentally in the first instance although the zoo now plans to make another attempt under more controlled conditions. Their theory is that a large group of fish is needed as spawning is hypothesised to occur en masse.

18 thoughts on “Denison / Red-line Torpedo Barb

  1. Hi, we were just looking for some info on torpedo barbs. My son has a 70 gallon tank and recently bought 2 torpedo barbs. Which to start with chased each other round the tank. Now one seems to keep the other in the the corner. And should it venture out of the corner he chases him back in there. We were contemplating buying a couple more barbs to help and perhaps a few rummy noses too. But we have seen that sometimes even that doesn’t work. Or do we give the aggressive one back and swap him. However, We were interested in your comments about a different type of more aggressive fish that is imported under the same name. Could you give us a little more info on this. Of the two fish we have the more aggressive one is more silvery with a fainter red and black line. There is no yellow body colour whilst the other is more vibrant. Are we barking up the wrong tree and just need to get more? Thanks Amanda

    1. I’d need to see good pictures of both your fish to ID them properly. Torpedo’s are sometimes mislabeled or mixed up with other similar fish although personally I have no idea how as to me they’re quite distinctive. They can be territorial though so even if they are both torp’s it could just be you have one which is a bully. It happens, you can try getting more redlines see if a bigger group helps sometimes it does sometimes it doesn’t a 70 gallon tank even in UK gallons is a reasonable size so assuming not too far overstocked you could probably have a couple more.

  2. I have a mix of trtras in my tank a capacity of 105 liters black neon tetras diamond eye tetras blue skirt tetras white tiped tetras halequim tetras rummy mode tetras two siemesse algae fish very non aggressive a cat fish a golden sucking loach all of them doing fine i think two denisonsi barbs would be ok . Surface water filter fairly fast what do you think ?

    1. 105 litres is a little small for torpedo’s but you may be OK if its a long ish tank they like room to swim about

  3. Thank you. Yeh ive done all three. Ive just upgraded filters to a fluval fx6 after upgrading my aquarium a few weeks ago plus i added a few smaller fish. They have stopped chasing now but still have no colour. They are still feeding so hopefully they should calm down and regain their colour thanks again

    1. If you’ve removed an old filter and just fitted a new filter without running them in tandem for a while to allow the new filter to build up its biofiltration bacteria then keep a close eye on your water parameters and do regular water changes small amount every day for a couple of week that should hopefully minimize any chance of a cycle or any impact of the new filter cycling up. Just for future reference never add new fish at same time as changing filters and always run new filters in tandem for a week or 2 allow them to build up before turning off the old ones.
      With regards to the fish as long as they’ve stopped chasing now you should be fine they should regain their colour over the next week or 2 just keep monitoring.

    2. Yeh i should of thaut about that to be honest but i put all the biological media stones in the new filter thinking that would be enough. The fish are beginning to regain their colour now but i will be keeping a close eye on them. Cheers

  4. Hi ive got a group of 3 redline torpedos which ive had for about 5 years. Now all of a sudden two of them are chasing each other and both have lost all their colouring on their bodies. They are in a live planted 110 uk gallon aquarium at 26 ‘c. Is this aggression or mating behaviour thanks

    1. Sounds more like general aggression something has upset them especially if they’re loosing their colour. Have the water parameters changed drastically/swayed? Have you introduced new fish or moved stuff around in the tank recently? It could have upset them a little. Hopefully they’ll calm down over time though.

  5. Hello, currently i own some Denison Red lined barbs including a single golden Puntius denisonii, which is a new colour morph. recently i have seen a change in one of my original Denison Barbs, which seems to have lost its black stripe and changed colours to look almost indistinguishable from the golden Denison. This change seems to have happened over the last 5 weeks. at first I thought it had a scale problem but I could not find the cause of the problem.
    I have obtained pictures of the current state of the fish and what it looked like before (original colours).

    Right= Transformed fish, Left= Original colours.
    Right= Transformed fish, Left= Original golden Denison.

    1. Wow they look amazing its the first time I’ve heard of them swapping like that though its not unheard of in fish. For example marine clown fish will swap sex male to female etc to create a pair. So its possible these have done something similar. It could well be worth while you documenting it all with lots of photos and if you want to learn more seek out an aquatic biologist at your local uni

  6. Hello, just thought I would post an update. I now have my 2 year old Denisons in a 4ft Juwel Vision with very large 300l external filter. I have put in a large pump and airstone which covers the entire back of the tank. New to the decor are two very big pieces of bogwood and all the plants are silk held down with rocks and slate. Wish I could post a picture! Unfortunately, I lost one of my Denison during the move and was devastated about it. I am now looking for a few more mature fish to add to the group. Has anyone got any to sell?

    1. Hi. I have a 3 torpedo barbs about 10cm each. They are in supreme condition fed on a diet of flakes and frozen food. They have outgrown their tank and I am looking to sell them on to fund smaller fish. Anyone interested ?

      1. Not really a classifieds site but ill let this fly 🙂 how much? What country? Where abouts in that country?

  7. My torpedo barbs are my pride and joy, I have 6 of them in my tank. I use a carbon filter which I change every month. However, I have recently been told not to use one because it can cause tissue waste in fish. Is this true?

    I have my denison barbs in a 3f / 180 litre tank. Is this tank big enough for them?

    1. The carbon in the filter will be fine as long as you change it every month or 2 it should cause no problems. The carbon helps keep the water clear and stable some people especially with heavily planted tanks will remove the carbon as it also removes any fertilizer added for the plans and can also remove other chemicals added to the water for medication etc but the general rule is the carbon is fine.

      As for the tank size a 3 footer is a little small for them as they can get potentially quite large fish when fully grown they like lots of flow and highly oxygenated water which you may not be able to achieve in a 3 footer without using powerheads which may on contrast not sit as well with your other fish. If they’re still small/babies then they’ll be fine in there for now but ideally you want to be looking at 4 foot or bigger for them as they like lots of room to swim about

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