Roseline Shark: The Ultimate Guide

So you’re considering adding a Roseline shark to your aquarium, and you’re interested in getting all the information you need about it in one place.

We’ve got you covered!

In this article, you’ll learn all about Roseline sharks, including their behaviors, tank requirements, breeding & feeding patterns, and health considerations.

Got a question? Feel free to check out our FAQ section later on in this post. You’ll find the best answers here.

An Overview of Roseline Shark aka Sahyadria Denisonii

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Roseline Sharks (Sahyadria denisonii) are beautiful freshwater fish that will easily catch the eye of any fish enthusiast or lover. They also go by the names Denison Barb, Miss Kerala, and red line torpedo barb.

These fishes are a great choice for a large community aquarium setup, and their colorful, friendly, and playful nature makes them a delight to watch.

If you’re thinking of getting them for your tank, read this guide first to gather all the essential information you need to know about this wonderful fish.

In this guide, we’ll cover everything you need to know about Denison barb fishes, including their habitat, behavior, tank requirements, tank mates, etc. We also included a FAQ guide to help answer any questions you might have about this fish.

Habitat and Origin of Denison Barbs

You can trace the origins of Denison barbs (Sahyadria denisonii) to Southern India, particularly Achankovil, Mundakayam, Cheenkannipuzha, and Chaliyar River. The Roseline fish is also native to India’s Kerala and Karnata parts, with a largely fragmented population.

That’s not all!

Other areas they inhabit in small numbers are Iritti, Bhavani, Kallar, and Sullya. The fish live in very oxygenated water in these river systems, and they tend to gather around the river bank where there is thick vegetation.

Here’s the catch:

This fish is rapidly decreasing in population in the wild because its popularity makes people capture it a lot for sale. Other factors for their shrinking population are the depletion of the resources in highly oxygenated freshwater and deforestation.

Behavior Types of Roseline Sharks (Spotting Their Gender)

It might be very difficult to determine the gender of a Denison Barb by just looking at it. If you plan to keep them in your tank, you should learn how to differentiate between the two.


The best way to tell the difference between the fishes is when they have sexual developments. You can use a thumb rule to identify the female and male fish in your tank.

A female Denison Barb is generally heavier-bodied and bigger than their male counterparts. Sometimes, you will also notice that the female fish is less brilliantly shaded than the male.

They also grow up with a more adjusted body.

On the other hand:

Males typically have the scarlet red color. Their body shape is always thinner with a formed body structure.

The Appearance of Denison Barbs

Denison barbs have a distinct elongated torpedo-shaped body that allows them to swim swiftly through the water. This unique shape has even given these fish species the name torpedo barb.

The torpedo-shaped body on these fishes also has a body color of silver and a black line that stretches from the snout to the fish’s tail. You might also see a bright scarlet line at the top of the black stripe running along the black line in the fish’s mid-body from the snout to the fish’s eyes.

Its caudal and dorsal fin is usually unique depending on the fish, but it generally has a colorful look. The caudal fin usually has a bright yellow and black color, while the dorsal fin is bright red.


If you’re looking for more flashy-looking fish, the golden Denison barbs are artificially created and have only red lines and no black stripes.

Caring for Roseline Sharks – Denison Barb Care

It would be best to keep your fish and tank in good condition if you had consistent care and maintenance. If you do not apportion the required time and resources for taking care of your tank, then you could be left with a terrible tank and dead fish.

Don’t just follow common misconceptions and myths people typically have about aquariums and caring for them.

It is necessary to know the tank requirements for taking care of Denison barbs and keeping them optimal. It would be best if you considered the following:

  • Tank shape
  • Tank size
  • Right water conditions

We will examine each of these a bit more in-depth below.

Tank Requirements for Denison Barbs

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The following are some of the requirements for setting up and making your tank compatible with Roseline Sharks.

Tank Size and Setup

It is important to note that a Roseline shark needs a lot of space in the tank. If your Roseline Shark fish has a 5 -6 inches size, you need a tank of 55 gallons or more so you can cater to them adequately.

Other factors to consider are keeping the appropriate water parameters, especially the temperature of the tank.  Generally, a red line torpedo barb can handle a wide range of water conditions and temperatures, including stale water and quicker streams.

This makes them a flexible network fish in many instances. Always try to keep your water temperature between 65 and 79oF.


Keeping a stylish layout is also as important as maintaining the water quality in your aquarium. You should always aim to mimic the natural habitat of a red line torpedo barb when setting up their tank.

You need the following equipment for mimicking their natural environment and making the tank suitable for them:

Filtration: You should put a water filter in your tank to purify them, and since the tank is most likely around size 55 gallons, canister channels are probably best.

Decorations: An aquarium without decorations look stale, especially one that will accommodate Denison barb fishes.

Lighting: Overhead lighting is a key component for setting up tanks for a Roseline Shark. This brings out their colors more brightly, and even though, like other freshwater fish, they are used to black water, you should make sure their lighting system is adjustable.

Shrubs: More fish in your tank mean fewer plants, and you should maintain this balance at all times with Roseline shark fish species. This makes the Denison barb fish feel more secure and gives them great hiding places from predators.

Substrate: Start applying substrate from the bottom of the aquarium with a layer of fine rock or sand. You can also put in a couple of stones and rock to the substrate to make it look more natural, as well as a couple of plants.

Aquarium Plants

Some of the best and compatible aquarium plants for a Denison barb tank include:

  • Cabomba
  • Java Fern
  • Bacopa Sp
  • Vallisneria

Breeding Roseline Sharks

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It is almost impossible to breed Denison barbs in your aquarium. If you try it, chances are the fish is just going to become stressed, and they die off.


Most of the Denison barbs fish available for purchase from local fish stores or online are typically from commercial breeders. These breeders get the fish from their natural habitat or use hormones to make the fish develop.

If you still decide to try breeding this fish in your aquarium, you should have at least 15 fish, so there is a higher chance of encouraging the spawning.

Denison Barb Tank Mates

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The best tank mates for Denison Barbs are other active swimmer fish and are about the same size. If you put smaller fish in the same tank as your Roseline Sharks, they might feel intimidated by their size and energy, leading them to get stressed fast.

On the other hand: 

if you put fish species far larger than Roseline sharks, they could eat or injure your Denison fish. Some great fish options are:

  • Large tetras
  • Zebra Loaches
  • Tiger Barbs
  • Kribensis Cichlids
  • Danios
  • Rosy Barbs
  • Yoyo Loaches

Here are some fishes you should never put in a Denison Barb Aquarium include:

  • Oscar
  • Discus Fish
  • Angelfish

If you also have any other options, you can put them in the tank as long as they aren’t overly aggressive fishes or have a large size difference with the Roseline Sharks.

You can also put invertebrates like snails and shrimps in the tank as they get along well as excellent tank mates with other fish. Always make sure to conduct deep research before putting any tank mate in your aquarium.

Putting Roseline Sharks Together:

It is recommended that you put Roseline sharks together since they are group fishes. They shoal and move around the tank together, which could be sometimes beautiful as they show off their color.

Keeping only one Roseline shark in your tank isn’t advisable as they could become lonely. This also makes them get stressed far easily and could make them contact diseases or other health issues.

Bottom line:

Make sure you have at least 6 Denison barbs in your tank.

Feeding Denison Barbs

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Feeding your fishes encompasses what you feed them, how much, and how often to do it. Always feed your fish quality food to keep them healthy and happy. Cheap foods have a lot of filler and will not give any nutrition to your fish.

How Much and How Often to Feed

Give your fish food twice a day to maintain a balance. When pouring the food into the tank, only run a quantity to finish in a few minutes.

What to Feed Your Roseline Shark

Roseline Sharks are omnivorous fishes, so you need to give them a mix of vegetable and meaty protein in their diet. These fish consume plant matter, algae, small invertebrates, and insects in nature.

If you have them in your tank, their basic diet can contain pellets, frozen foods, and tropical fish flakes. You can also boost their natural color by giving them carotenoids.

Try to mix up the diet by adding live and frozen foods, including:

  • Brine shrimp
  • Spirulina
  • Bloodworms
  • Daphnia
  • Blanched vegetables

Health and Diseases of Denison Barbs

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Keeping your Denison Barbs safe and healthy is the key to making sure they survive in your tank for long periods. This fish is hardy normally, but you should also give them clean and clear water to support them. If the water is dirty, this could get them stressed and make them susceptible to diseases.

Red Flags

Here are a few signs that could be a sign that your fish has a disease:

  • Lethargy
  • Swelling
  • Poor appetite
  • Ulcers
  • Rubbing their bodies against tank décor
  • Not swimming with the school
  • Red patches on the skin

Common Health issues And Solutions

While it would be better to avoid diseases completely, sometimes they occur. Here are some common health issues in Denison barbs, how to spot them, and solutions you can use to resolve them.

Health issue: White Spot Disease (Ich)

Causes/Symptoms: It is a common disease that is a result of an aquatic protozoan parasite. A fish with this disease has tiny white spots on their gill covers, fins, and other parts of their bodies. You should also keep an eye out to notice if they flash against gravel or other solid items in your tank.

Action: Increase the water temperature to 82oF for three days. Afterward, use an OTC White Spot Disease medication to treat your tank.

Health issue: Bacterial Infection

Causes/Symptoms: Red spots and areas on ulcers, skin, and sores.

Action: Purchase antibacterial medication and use it to treat the tank.

Health issue: Skin and Gill Flukes

Causes/Symptoms: A fluke is a parasitic creature that attaches itself to the gills or body. A fish with this infection rubs their body against the substrate and ornaments. They also secrete excess mucus from their body.

Action: Separate the affected fish from the rest and quarantine it. Treat your tank water with antifungal treatment before another fish gets infected.

Health issue: Fungal Infection

Causes/Symptoms: White cottony growths on the fish body.

Action: Separate the infected fish. Treat the tank water with antifungal medication to purify it.


Are Roseline Sharks Actually Sharks?

No, Roseline shark fish isn’t a shark. Even though they have a shark in their name, these fishes aren’t freshwater sharks.

Are Roseline Sharks Aggressive?

Denison barbs are generally peaceful fishes, especially like other fishes in the same tank. They form fish schools and move across the aquarium this way because they are very active fish.

However, they do not fit into small aquariums or tank mates with similar sizes, and some owners have reported aggressive behavior when you keep them in small spaces.

Sometimes, they are also aggressive with their kind, but this is limited, and we will still call them peaceful fish relative to other species.

Bottom line:

If you want peaceful Denison barbs fish, give them plenty of space in the tank.

Are Denison Barbs Fin Nippers?

No, Roseline Shark fish aren’t known as fish nippers. The only time you should have this concern is when you place them in an aquarium with similar-sized fish or larger ones. It is always best to place Denison Barbs fishes in schools of aquarium size tanks that are 55 gallons at the minimum.

How Big Does a Roseline Shark Get?

The sizes of Denison Barbs vary, but they can grow to lengths of up to 6 inches. This is why we cannot emphasize enough the need to keep them in a large tank with enough space.

Are Denison Barbs Endangered?

Yes, Denison Barbs are an endangered fish species. There has been a drastic reduction in Denison Barbs fish because of overfishing, popularity, and deforestation.

Breeding programs in Eastern Europe and Southeast Asia have programs to help preserve their existence by practicing shark breeding in their facilities. India also has restricted activities that involve wild hunting Denison barbs to reduce the depletion and increase their population.

Do Denison Barbs Lose Color?

Yes, a Roseline Shark might lose its color when you push them to its limit or if there is a considerable adjustment in the aquarium water structure. Other factors that can make them lose their bright hue color include new tank mates and changes in conditions/climate.

Transportation-induced stress and climate change also make them get noticeably paler.


If you notice your fish is losing its color, check out all the factors listed above and make necessary changes as necessary.

Try Out The Roseline Shark For Yourself

Denison Barb is a colorful, beautiful, and very active fish that typically move together in communities. They stand out by their colors and very active lifestyle, making them a fun addition to an aquarium.


They need a large aquarium size and many other requirements, making them less than ideal for beginners. If you have space and can live up to the requirements for keeping them, go for it. They’re an excellent choice.

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