Roseline sharks make a fantastic addition to a large and well-planned community tank when they’re housed correctly. They’re colorful, bright, active, and inquisitive. They’re easy to feed, they’re peaceful when they’re housed in the appropriate numbers, and they play well with most large (relatively) peaceful cichlids as well.
However, roseline sharks aren’t ideal beginner fish, nor are they ideal fish by most standards. They’re endangered in the wild, get relatively large, need space to swim, also a good amount of plant coverage, a decently high number of fellow roselines, faster-flowing water, and pristine water chemistry.
They’re definitely not the kind of fish you can be lazy with either, particularly because they’re endangered. So they’re not for the lazy fish keeper.
With that said, they make a phenomenal display that’s always full of color, life, and fun. So if that sounds like the kind of fish tank you want, read on to find out everything you need to know about keeping these endangered beauties.
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Table of contents
Table of Contents
FAQ
Are Denison barbs aggressive?
They can be aggressive with their own kind and, occasionally, with other species of similar-looking fish. But their aggression is limited and they’re usually pretty peaceful and only get rowdy when there’s not enough of them in the tank.
What do roseline sharks eat?
Roseline sharks aren’t picky about food and will eat almost anything that’s offered to them. They do like sinking food more than they like eating from the surface, so floating food will likely go unnoticed until it sinks.
Are roseline sharks hardy?
Not particularly, no. They need highly oxygenated, pristine water. They don’t handle tanks that aren’t well cycled or any levels of ammonia, nitrates, or nitrites.
Sahyadria denisonii Classification
IUCN Status: Endangered – Last assessed 7/6/2010
Class: Actinopterygii are ray-finned fishes, which is a subcategory of boney fishes. These fish are characterized by the bony structures that support their webbed fins. This group makes up nearly half of all living vertebrates.
Order: Cypriniformes includes over 400 genera (the plural for genus) and more than 4,200 species of carp, minnow, loaches, and relatives.
Family: Cyprinidae, or collectively called cyprinids or the “carp family,” is composed of egg scattering species that exhibit no parental care.
Genus: The Sahyadria genus was previously included in the Puntius genus and only consists of two species; Sahyadria chalakkudiensis and Sahyadria denisonii.
Species: Sahyadria denisonii (formerly Puntius denisonii)
What Does Sahyadria denisonii Mean?
Sahyadria comes from the Sahyadri, which is a local name for the Western Ghats mountain ranges.
Denisonii comes from Sir William Thomas Denison (1804-1871), governor of Madras, India, from 1861-1866. Though he was the governor of Van Diemen’s Land from 1847 to 1855 and governor of New South Wales from 1855 to 1861 as well.
In modern cases, being named after a political figure might leave a certain air of… judgment. But, by all accounts, Denison was a well-liked and well-respected man, so it’s a pretty big compliment.
Find Other Fish
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Distribution & Natural Habitat
Denison’s barbs are endemic to Kerala and Karnataka in southern India. The population is highly fragmented and, as far as we’re aware, populations exist in small numbers in the Valapatanam, Chaliyar, Kallar, Karyangod, Kuttiyadi, Chandragiri, Sullya, Kuppam, Iritti, Anjarakandipuzha, Bhavani, and Bharatapuzha river systems.
They’re usually found in highly-oxygenated headwaters and upper parts of river basins within those river systems. They can be found congregating alongside the banks where vegetation is thick or in rocky pools.
Aquarium Care
Difficulty: Easy, but special care needed
Size: 5.9″ (15 cm)
Lifespan: 4 – 5 years
Tank Size: 55+ gallons (220+ liters)
Diet: Omnivore – easy to feed
Temperature: 59 – 77 F (15 – 25 C)
Like most barbs, these guys are great jumps, so you’ll need a lid. They also tend to get wound up and more aggressive towards each other around dusk and dawn, so avoid feeding them around those times to minimize aggression. Though they can reach 5.9″ (15 cm), they typically don’t get larger than 4.3″ (11 cm.)
Tank Specs
You’ll need at least a 55 gallon, though a 75 or a 90 would be much better for them. They can get large, they’re fast, and they swim constantly, so they could really use the additional space to flex their fins. Not only will their behavior be more natural and fun to watch, but they’ll also likely grow to their fullest potential.
Movement is a big factor that relates to fish’s growth rates and final adult size.
Even beyond size and space to move, a larger tank will make maintaining their pristine water quality much easier. And, again, these guys are endangered, so you should be giving them the best home you can – even though yours are captive bred.
They do great at room temp, so there’s not a huge need for a heater. If you want to add a heater and keep it set to a lower temperature to keep the water stable, that’s a great idea – but just make sure you get an external controller or alarm system for redundancy. Overheating Denison barbs is far more dangerous than underheating.
I have an article that covers the best heaters (as well as controllers, alarms, thermometers, and accessories) if that’s the path you want to take.
Stocking
Roselines are shoaling (not schooling!) fish and most places say a minimum of six. If that’s literally all you can do, yeah, six makes sense as a bare minimum. But if I was going to give advice based on ideals and instead of what I thought people might be willing to do, 12 or more is a much healthier number.
Denison barbs get big and – not really aggressive but… rowdy. So the more you have, the more the aggression gets spread out and the more complex and less aggressive their hierarchy becomes. Not to mention the only reports of successful breeding comes from tanks with 15+ roselines. Even if you’re not going to breed them, you should take that as a cue.
Fish only spawn when they’re happy, healthy, and feel safe. So if breeding only happens when there’s 15 or more in a single tank, that should tell you that anything substantially under that (like six) is nowhere near enough to make them happy or feel safe.
Decor
Denison barbs are inquisitive, they’ll explore nooks and crannies if you give them the opportunity to. But they’re also large and fast, so I would avoid anything that can easily damage them while they’re zipping around. Things to avoid would be sharp rocks, caves they can get stuck in, and sharp pieces of driftwood. Especially if they happen to be somewhere in their path for swimming.
Plants and river stones are the way to go here for decor. Since they’re not picky about substrate, anything works for that, really. Again, I would avoid anything sharp – but river stones, HTH pool filter sand, or planted substrates will work well for these guys. If you’re not sure what to look for in a planted substrate, I have the best below.
Best Plants For Roseline Sharks
The fewer roseline sharks you have in your tank, the more plants you’re going to want to make sure they feel safe and have an escape route from aggression. You’ll want to look for plants that can deal with a moderate flow rate and are tall enough to provide good cover, but aren’t going to take up a ton of swimming space.
If you’re having issues with your barbs being particularly jumpy, you can try some floating plants. But floating plants don’t usually do well with water movement and Denison barbs don’t come from areas where floating plants exist, so it’s not the most natural option.
Guppy Grass
Guppy grass is a great floating plant that adds depth, structure, and cover to any tank. It’s a super easy plant to grow and takes up tons of ammonia, nitrates, and nitrites, but – beware – it grows fast and can easily overrun your tank. Overall, it’s an amazing plant to have if water quality is your top concern.
Pennywort sp.
There are quite a few species of pennywort, but most have similar care requirements and grow quickly. Because they can be grown in or out of the water, in a variety of ways, and in a wide range of conditions, this makes them a super adaptable aquarium plant. They also make exceptional plants for summer tubs!
Vallisneria
Vals come in a ton of varieties, but most of them are about the same to grow. They can grow rapidly, and quickly cover your tank with lush, kelp-like forests for your fish. Some species, however, do grow much shorter than others.
Bacopa sp.
Bacopa comes in a variety of species and variants – some more demanding than others – but the least demanding is Bacopa carolinia. It is banned in a few states because of its invasive species status, but it makes a wonderful addition to most aquariums if you can get it.
Cabomba sp.
There are several species of cabomba, the green is the easiest. It’s difficult to get in certain states because in some places it’s considered invasive. Somewhat ironically, we seem to struggle growing it in aquariums. If you can get your lighting high enough, it’s worth it.
Lighting & Filtration
Denison barbs are one of the few fish that I can think of that don’t care a ton about overhead lighting, so you don’t have to worry about blocking it. Their filtration, however, should be at least moderately fast and – of course – well-cycled.
Given the recommended size of the tank, HOBs aren’t going to be the best option to turn over your tank, so I’d recommend canister filters to get the job done. You’ll want to look somewhere in the range of 4x – 6x turnover per hour. To find the GPH you’ll need, multiply the size of your tank by the turnover and that’s the number you’ll want to look for.
I would also suggest looking for something adjustable so you can easily scale up or down the flow to whatever makes your barbs happiest. If you don’t know where to start with canisters, I have the best options listed below.
Water Care
Roseline sharks aren’t tolerant of any pollutants, so you’ll need to be on top of water care and make sure you have a well-cycled filter. Depending on your tank size and how stocked your aquarium is, you might be able to do 25% water changes every other week, but 25% weekly water changes would definitely be better for the stability of their water.
Of course, when we’re talking about 55+ gallon aquariums, that’s a lot of water every week and definitely too much for the average person to want to lug buckets. You’ll probably want to invest in a Python (or something similar) so you don’t have to carry 100+ lbs of water to and from your drain. A Python is an investment, but an investment that’ll (literally) save your back.
Aside from water change equipment, you’ll also want a good dechlorinator and a handful of meds to prevent disease from wiping out the shoal. If one fish gets sick and isn’t treated quickly, there’s a good chance most of your fish will get sick, so having these meds handy before you need them can be a lifesaver.
Feeding Roseline Sharks
Roseline sharks are ravenous and will eat just about anything you offer them. They prefer to eat their food mid-water or from the bottom of the tank, so I would avoid anything floating as it’ll likely pollute your tank long before it gets eaten but, otherwise, anything goes.
One thing to keep in mind is that even though they’re relatively large fish, their mouths aren’t quite as large as you’d expect.
Anything small enough to feed a betta is a good size for even large torpedo barbs.
White worms, tubifex worms (freeze-dried), blackworms (freeze-dried), brine shrimp, mysis shrimp, bloodworms, and glassworms are all great choices. As are sinking pellets like Bug Bites, Repashy (spawn and grow is my favorite,) and some foods with plants like algae wafers are great ways to round out their diet.
Again, they’ll take basically anything, but if you’re lost on where to start I have a handy shopping list below that might help.
Common Roseline Shark Diseases
The biggest killer of roseline sharks is bad water. Even if they have a disease, it probably came from bad water. Before you try to treat the disease, you should treat the source. Your ammonia and nitrites should be at zero while nitrates can safely be somewhere around 5ppm, but definitely not more than 10ppm.
Aside from that, they tend to have relatively few problems that they’re prone to and – again – all of these are a result of bad water quality or being kept improperly, so make sure you address the underlying cause as well if your roselines get sick.
Bacterial Infection
Bacterial infection is a broad term, the bacteria family can cause a wide range of symptoms and come from varying causes. Generally, you can treat them with a broad spectrum antibacterial regardless of the particular bacteria at hand. It’s diagnosing that’s usually the hard part.
Making matters even more difficult, fish can have an internal or external bacterial infection.
Symptoms:
- Red streaks
- Red ulcers
- Fuzzy growths
- Pop eye
- Bloating
Causes:
- Poor water quality
- Food that’s gone bad
- Keeping fish in inappropriate water parameters
- Stress
Fungal Infection
Fungal infections are a tricky bunch – not only do they have a huge family that presents a wide variety of species and symptoms – but some bacterial infections look strikingly similar to a fungus.
If you’re not sure if you’re dealing with a fungus or a bacterial infection, I find it helpful to treat with Ich X and Erythromycin (provided it’s 100% erythromycin) at the same time to be sure I’m treating for both.
Symptoms:
- Cottony growths on body, fins, eyes, and/or gills
Causes:
- Prior untreated injury
- Stress
- Water quality-related issues
- Prior untreated infection (bacterial, parasitic, etc.)
Swim Bladder Disease (SBD)
If your fish is swimming oddly, is having trouble swimming, or seems to be unable to control the direction it’s going in – it likely has a swimbladder issue.
There are numerous reasons why fish develop this (and not all of them are understood) so treating SBD can be hit-or-miss depending on why it got it in the first place.
Symptoms:
- Floating upside down
- Sinking to the bottom of the tank
- Standing on their head
- Inability to keep upright
Causes:
- Bacterial infection
- Cysts
- Fatty liver tissue
- Egg bound (females)
- Parasites
- Diet-related issues
Bloat
Bloat certainly doesn’t have to be as severe as the picture, but you get the idea. Bloating is an accumulation of gas, fluids, or unpassed food present in the fish. Although I have no proof, I suspect this is why most people search “how to tell if [insert fish species] is pregnant” even if they can’t get pregnant. There is a difference between a bloated fish and a fish that’s eaten too much – the fish that ate too much will act normal whereas the other usually won’t.
Symptoms:
- Your fish’s stomach is distended without raised scales
- Fish may appear to be in some sort of discomfort and avoid swimming or other usual activities
- May not be pooping
Causes:
- Intestinal blockage
- Constipation
- Internal bacterial infection
- Internal growths/tumors
Columnaris (Cotton Mouth Disease)
Occasionally called false neon tetra disease or cottonmouth, this is caused by a gram-negative bacterium. it can also, quite understandable, be confused with fungal infections.
Symptoms:
- Discolored scales
- Scales appear to be popping off (not “pineconing”)
- Grey spots
- Lesions on the back
- Legions around the mouth
- May result in fuzzy patches due to secondary infections
Causes:
- Flavbacterium columnare (bacteria)
12 Great Roseline Shark Tank Mates
Of course, this isn’t a complete list of tankmates. There are certain geophagus, cyprinid, and smaller more active catfish – like pictus and raphaels – would work. But these 12 are the fish that I felt like would do the best in most moderately-sized aquariums.
If you want to go off this list (and I encourage you to explore other options!), you’ll want to look for fish that aren’t easily intimidated but aren’t aggressive, unpicky fish that are quick to grab food, and fish that do well in highly oxygenated tanks at moderate temps. This rules out basically any blackwater species, but leaves a ton of Asian and South or Central American species open.
Red-Tailed Rasbora (Rasbora borapetensis)
Not the easiest fish to find, and you’ll likely need to special order them, but they make great community tank inhabitants. They’re hardy, peaceful, colorful, and not easily spooked. You’ll want to get them in shoals of 8 – 10, though likely order more in case of casualties.
Golden Dwarf Cichlid (Nannacara anomala)
Golden dwarf cichlids make a great addition to most well-planned community tanks. So long as they’re not spawning or protecting fry, they’re peaceful fish that aren’t bothered by other fish or easily intimidated.
pH: 5.5 – 7
dKH: 1 – 10
Temp: 72 – 77 F (22 – 25 C)
Size: 3″ (7.5 cm) max
Temperament: Peaceful and active
Swimming: Mid to bottom
Harlequin Rasbora (Trigonostigma heteromorpha)
Harlequins are a shoaling species that prefer friend groups of six or more. They’re not known to be nippy fish and are quite peaceful as long as they’re provided plants, space to swim, and the company of their own kind.
pH: 5 – 7.5
dKH: 1 – 12
Temp: 70 to 83 F (21 to 28 C)
Size: 2″ (5 cm)
Temperament: Peaceful
Swimming: Mid to top-water shoaling
Leopard Danio (Brachydanio froskei)
Leopard danios have amazing color and, if you look hard enough, you may even be able to find some dazzling color morphs of this fish as well! They do best in groups of six or more and zip around the tank quite a bit, so ensure you have swimming space for a shoal of this size.
pH: 6.0 – 8.0
dKH: 2 – 20
Temp: 64 -75F (17 – 23C)
Size: 2.4″ (6 cm)
Temperament: Active
Swimming: Mid to top
Zebra “Danio” (Brachydanio rerio)
Zebra danios belong to the minnow family. They’re fast, outgoing, peaceful, and need room to swim with their shoal (6 or more being ideal.) They can handle a range of temperatures and water conditions – from stagnant to faster-flow, making them a versatile community fish.
pH: 6.0 – 8.0
dKH: 5 – 20
Temp: 65 – 77 F (18 – 25 C)
Size: 1.5 – 2″ (4 – 5 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling
Bolivian Ram (Mikrogeophagus altispinosus)
The underrated cousin to the German Blue Ram are often nearly colorless and shy in the store tanks. But provided with the right tank and dither fish, they’ll color up and exhibit fascinating behavior in your home aquarium!
Keep in mind these rams will also become territorial while spawning. However, there are some sparse reports of other tankmates going unnoticed during spawning.
pH: 6.0 – 7.5
dKH: 1 – 10
Temp: 68 – 83 F (20 – 28 C)
Size: 3″ (8 cm)
Temperament: Peaceful
Swimming: Bottom to mid-water
Corydora (Corydora sp.)
While each species will vary slightly, all require smooth substrates or bare bottom and do best when they’re kept in groups of at least six or more.
Some larger options would be better here, anywhere from 2.5″ (6.5 cm) and up. Good candidates would include bronze, emerald, Sterbai’s, and peppered cories.
pH: 5.5 – 7.0 – species dependent
dKH: 3 – 10
Temp: 72 – 80 F (22 – 26 C) – species dependent
Size: 1 – 3.5″ (2.5 – 9 cm) – species dependent
Temperament: Peaceful, can be boisterous for less active species
Swimming: Bottom (most) in a shoal of 6 or more
Silvertip Tetra (Hasemania nana)
If you like fish that will follow your finger like ravenous sharks, these are your fish. They’re a nearly unspookable little shoaling fish that like to be kept in groups of six or more.
pH: 6.0 – 8.0
dKH: 5 – 20
Temp: 74 – 82F (23 – 28C)
Size: 2″ (5 cm)
Temperament: Active shoaling fish
Swimming: Mid to top
Bristlenose Plecos (Ancistrus sp.)
Most plecos aren’t suited for the average aquarium, some growing up to two feet long – not the bristlenose pleco. They’ll happily munch on algae, green beans, zucchinis, cucumbers, sinking algae wafers, and of course leftovers and fish poo – although leftovers and poo make for a literally shitty diet.
pH: 6.0 – 7.5
dKH: 6 – 10
Temp: 60 – 80 F (15 – 27 C)
Size: 4 – 5″ (10 – 12 cm)
Temperament: Peaceful, can be territorial
Swimming: Everywhere that has structure
Celebes Rainbowfish (Marosatherina ladigesi)
Celebes rainbowfish can be difficult to find and tricky to keep if not kept properly. They need to be housed in groups of at least 6 and do best in a planted tank.
pH: 7.0 – 8.0
dKH: 10 – 20
Temp: 72 – 82 F (22 to 28 C )
Size: 3″ (7.5 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling
Dwarf Neon Rainbowfish (Melanotaenia praecox)
Dwarf rainbowfish do best when kept in groups of at least 6, though more is always better. Once they’re fully mature and settled, they develop beautiful colors when given lots of plants and open space to swim.
pH: 6.8 – 7.5
dKH: 5 – 15
Temp: 73 – 82 F (23 – 28 C )
Size: 3.2″ (8 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling
Emperor Tetra (Nematobrycon palmeri)
Emperor tetras are one of the best community tetras you can find. They’re hardy, easily adaptable, peaceful, and large enough to not be easily startled. They’re best kept in shoals of 6 or more, with 10 or more being better.
pH: 5.0 – 7.5
dKH: 1 – 12
Temp: 74 – 81 F (23 – 27 C)
Size: 2″ (5 cm)
Temperament: Peaceful and active
Swimming: Top to midwater shoaling
Breeding Roseline Sharks
There’s not a whole lot of information about how torpedo barbs spawn or how to accurately sex them. Though typically, females are larger and heavier bodied and males tend to be redder. The information we do have seems to indicate that most of the time they’re spawned accidentally in home aquariums and need to be kept in groups of at least 15 to trigger spawning.
Or perhaps they spawn in large groups because most of the time Denison barbs are males and you need a large group to get enough females.
Spawning
There are only two reports I found of spawning in home aquariums – both were accidental and fry were found hiding in the plants. So if you want to attempt to spawn them, you’ll definitely want some cover for any potential fry.
All the information we have – which is very little – points to them needing a group of 15 or more fish and a gradual lowering of pH to spawn. One successful attempt reported their parameters as a dKH 2 – 3 and pH 5.7. They had gradually lowered their pH and dKH by using driftwood and prior to spawning, the dorsal fin of the fish changed to a blue color.
The fish laid eggs in java moss, but it’s unclear if they were presented with more options and moss was a critical part of their spawning behavior or if they were only presented with moss, so the fish used what they had available. Though some sources say that fine leafed plants are needed, mosses or otherwise.
Egg & Fry Care
There’s no accurate or reliable information on egg or fry care, though the parents certainly exhibit no parental care and fry should hatch large enough to eat baby brine shrimp and grow rather quickly. It’s also quite likely that the parents would be willing to eat their own offspring, because most fish do, but also because roseline sharks are voracious eaters.
The best plan of action would be to remove any eggs or fry from the parent’s tank and place them in a 20 or 30 long until they’re large enough to be moved. The smaller quarters makes cleaning the tank – and keeping it clean – a little more of a challenge, but it ensures the fry will be able to easily find food.
Fecundity is reportedly low in this species, but I could find no cited sources to back this information up, so take that with a grain of salt and some relativity. For sake of relativity, most cyprinids of relative size can produce about 700 eggs at any given time, so even with relatively low fecundity, they’re likely capable of producing large batches of fry. But, again, there were no studies I could find to confirm or disprove relative fecundity.
Types Of Roseline Sharks
There’s only one variant of torpedo barb, and that’s the gold roseline shark. Unlike most color mutations, this one does not appear to be from any hybridization or intentional genetic modification.
Initially developed from natural mutations in commercially bred Denison barbs, the gold roseline has a bright yellow color instead of the normal silver, and most are missing any natural black coloration on their body.
