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.

41 thoughts on “Denison / Red-line Torpedo Barb”

  1. My six year old Redline has developed a bloated physique and raised scales all over its body. His color has faded a bit, too. Water temperature is 77f (it used to be 80f); feed is flakes and bloodworms. All is unchanged since mid August, except for the new Fluval E300 water heater. 100 US gallon tank.

  2. Hi i kept fish for 15 years never really had many problems, had one or 2 over years but leard by them.
    I have many diffrent fish clown roach plecos angle fish,
    i have group 7 torpedo barbs found one upside down bottom of tank,
    i got it in same tank got him in breading box 3 days now so dont get eaten by other fish,
    still alive on his side carnt stay up right
    all other fish fine,
    did water change last saturday and cleaned exteral filter all ok

    1. sounds like swim bladder, have you tried not feeding him for a couple of days it should settle down and resolve its self hopefully.

  3. I bought 3 red line torpedoes and one has white round its nose, another one keeps chasing it. Is it a sore,

    1. They like to be in larger groups and need quite a big tank if they’re in a small group or a small tank they get very territorial.

  4. Hi guys, I’ve just bought a couple of new barbs to go into my tank. Whilst acclimatising them one went missing in the bag. It’s justt completely gone! Any ideas on behaviour? Can they jump? Do they hide when they join a new tank? Any help is appreciated please?

    Thanks, Adam.

    1. yes barbs jump a lot and very high and they will hide when introduced to a new tank. if its not in any of your growth etc i’d check around the tank.

    2. Hi guys, just looking for a bit of advice.

      We’ve have our red lined torpedo barb for about 3 years now and never had any problems. The last couple of days he’s been swimming erratically around the tank then just laying at the bottom looking dead? He sometimes goes upside down which made me think he had swim bladder, I have treated him for that but is there anything else it could be?

      T.I.A x

    3. Hi guys,

      Just looking for a bit of advice, we’ve had our red line torpedo barb for about 3 years now and had no problems, all of a sudden the last couple of days hes been swimming erratically around the tank, then just laying at the bottom? He goes upside down sometimes aswell which made me think it was swim bladder so I have treated him for that but is there anything else it could be?

      T.I.A x

  5. Hi I have 3 red line torpedo barbs amongst other fish which I’ve had for nearly a year and all have been fine but yesterday did my normal weekly tank maintenance and water change but I got up this morning to my filter not working so no water bubbles.
    This is an extra filter I use because I have a large under tank filtration system but this gives the water bubbles and aireation.
    All my fish were gasping at top of tank,checked water all okay so thought it must be because the filter bubbles were not there so have sorted that out and is now working again(don’t know why it stopped)
    Would this be the cause of this because an hour later the barbs are still at the top and they have never done this cause they have always swum around happily but now I think I’m going to loose them.
    Ant advice would be greatly appreciated

  6. Hi
    I have had my red lines for over a year now…they are growing well and seem very happy in the tank.
    However, while all other colours have stayed the same one of them has gone a lot darker..almost black..all his other features and colours are still predominant and stayed the same.
    Can you think why this may be?

    1. Its probably stress related although usually they lose their colour rather than go darker, a picture would be interesting just to compare how much darker than the others its gone.

  7. Hi

    I have 3 large Torpedos in a 4 foot tank who live peacefully with each other. I have decided to add 2 more younger ones and one of the smaller has decided to harass all the larger ones! He will keep swimming underneath the larger ones and then nip the underside. He also has a go at the rummy nose tetras. Is this normal for Torpedoes? I’d have thought if anything the larger ones would’ve attacked.

    1. Just like people they all have their own personality could be you.just have an aggressive one or could be too many in a tank that size and one has taken offense at the crowded surroundings. Could also be the new one trying to assert himself as a dominant male just eye on it for now but if it continues you may have to remove him

    2. Barbs of all kinds are reknown for nipping, they are best in groups of 8 or more. Denisons in particular need very clean airated water as they are river fish so they need lots of water changes! 25% bi/weekly. Usually nipping is due to a stress trigger or just the nature of that particular fish’s temperament. Best action is to remove the offending fish or keep a larger group and check your aquarium for stress factors such as water quality.

  8. These fish should not be kept in small groups. 7 minimum for sure, I’ve kept them for almost 15 years now and I know this for certain. I thought I would comment since I see some people posting have kept 1 or 2 etc.

  9. We have a Denison barb who is losing his color but onky in the middle of his body. He doesn’t seem to be under stress but we don’t know what else can be causing this. Any ideas/suggestions how to help this fish??

    1. Have you added new fish recently? Rearranged tank? Given it a good clean out or a large water change? All these things can lead to them becoming stressed also have you checked your water parameters recently make sure it’s still good quality water it does seem to be redlines are more sensitive to the quality than some other fish

  10. I just got a Juwel Rio 240 litre (52 gallon) with a Eheim pro4+ 350 and I wonder how many torpedo barbs i can have in this aquarium.
    From my old aquarium i will transfer 3 SAE and 8 Kuhli and i have 8 cory trilineatus that might have to go in the 30 gallon or do you think they can go in with the barbs in the new one?

    1. Really that’s about the size for one but I would personally go for 2 since they’re small when you get them from fish shops (too small usually but that’s a different story) just don’t be surprised if you have to move on won in a couple of years as they do get to be quite big fish

  11. We have just bought two Denison Barbs and introduced them to our community tank. They are lovely but we are concerned that one of them in particular is spending most of its time in a perpendicular position and is quite lethargic. We have had them just two days. Any thoughts?

    1. One of them could have a little tank shock or perhaps having swim bladder issues. Keep an eye on them if he’s not sorted himself out after a week do you have a separate tank to move him in to see if he settles outside the main tank? Is the water quality good and with good oxygenation?

  12. 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.

  13. 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

  14. 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

  15. 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.

  16. 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

  17. 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?

  18. 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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