Roseline shark, also known as a Denison Barb, in a gravel tank

Denison Barb Care (Roseline Shark): Types, Tank Setup, Diet And More

The Denison Barb, otherwise known as the Roseline Shark, is a wonderful addition to large, well-planned aquariums. They’re colorful, active, and inquisitive which makes them an attractive option for many aquarists. 

However, they’re an endangered species in the wild and require a large tank, pristine water conditions, good flowing current, and can grow relatively large in captivity. As long as you know what you’re getting into, Denison Barbs can be an awesome addition to your large aquarium set-up. We wouldn’t categorize them as ideal beginner fish but if you’re willing to learn, we feel confident that a beginner can handle them with the right set-up.

Below, we’re going to discuss everything you need to know about Roseline Sharks. We’ll review their tank requirements, diet, lifespan, and more so that you can safely include these beautiful fish in your aquarium.

Recommended Denison Barb Care Items:

Denison Barb/Roseline Shark Appearance

The Denison Barb (scientific name: Sahyadria denisonii) is a beautiful, colorful, freshwater fish species. The body of the Dension barb is long and slender with a silver base. Some make references to the fish looking like they have torpedo-shaped bodies.

Roseline Sharks have a black lateral stripe running the length of their bodies, from their snout to the base of their tail fin. Above their black stripe, they have a red stripe that originates at their snout and runs until their mid-section. Red can also appear on their dorsal fins.

They also often have yellow and black striping on their tail fin. Their tail fin is forked and the yellow color patterns emerge on both tips. Lastly, mature specimens will often present with an emerald green color on their heads, making them some of the most colorful freshwater fish around.

It can be difficult to distinguish sexes in the Roseline Shark. Females are typically larger and duller in coloration.

Tank of Roseline Sharks swimming together

Denison Barb / Roseline Shark Size

Roseline Sharks can get big! The average size is around six inches in length when fully grown. Because they’re so large for aquarium fish, their colors are very visible, which makes them a highly-valued species choice.

Denison Barb / Roseline Shark Lifespan

With ideal living conditions and diet, Denison Barbs can live up to four or five years in captivity. They need a clean aquarium, healthy diet, and pristine waters to reach this age. Any shortcuts on their care will likely lead to a reduced lifespan.

Denison Barb / Roseline Shark Care

Caring for your Roseline Shark will be reasonably straightforward. Their active lifestyles and sensitivity to water changes will require slightly more attention and skill than typical beginner fish but are totally doable if you’re prepared. Here are several things you should be prepared for before introducing these fish to your tank:

Habitat

First, you’ll want to set up your tank to mimic their natural habitat as closely as possible. These fish naturally live in fast-moving streams and rivers in Western India, so your tank will require numerous places to hide, lots of room to swim, and some fast-flowing currents. Without these elements, Roseline Sharks can become stressed and lose their coloration.

Tank filtration should be at least moderately fast and well-cycled. Canister filters are ideal. You will want to look for a range of 4x – 6x turnover per hour. To find the gallons per hour (GPH) you’ll need, multiply the size of your tank by the turnover. For example, if you have a 55 gallon tank and you’re looking for a 5x turnover, you’re looking for 275 GPH. You will also want something adjustable as flexibility and adapting to what makes your fish the happiest will be key in supporting a long and healthy life.

It is a great idea to add live plants to the tank. Again, the idea is to mimic the natural environment. Additionally, you will need plants that can deal with the moderate flow rate so they need to be hardy. Additionally, plants that provide adequate hiding opportunities without impeding swim lanes will be important. Plants like Hornwort and Java Ferns could be good fits. Plants should be anchored in tanks, as Roseline Sharks love rooting around and uprooting plants.

Lastly, add a few hiding spots to the tank. You can add rocks or driftwood for a natural look and provide the fish with privacy if they want to escape for a little bit. Avoid adding too many items to the tank as the most important element is creating a large, open space for swimming.

Additionally, it is ideal to create good water flow via currents, as the Roseline Sharks are a river fish where they have to swim with currents. 

Lastly, put a lid on the tank! Roseline Sharks can be jumpers so the best way to keep them in the tank is to keep a lid on it.

Tank

55 gallons is the minimum recommended size. A 75 or a 90 gallon tank is ideal. Roseline Sharks can get large and swim constantly so the extra space is very beneficial to their development.

From a fish-keeping perspective, a larger tank is also easier to keep stable and clean. Water conditions are easier to balance in larger tanks, which is why so many beginners go astray with small tanks.

Roseline Sharks do well at room temp so you can skip a heater here, unless your house is very chilly.

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Tetra 55 Gallon Aquarium Kit
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What We Like

  • Lots of space to be creative with fish and decoration choices
  • Easier to maintain water quality with the larger volume

What We Don’t Like

  • Some consumers reported their tanks arrived damaged
  • Depending on tank requirements, might need to replace filter

Water Conditions

Roseline Sharks come from highly oxygenated streams and rivers with water that is constantly turning over and getting exposed to oxygen. These rivers and streams are also full of vegetative matter that provides safe places to hide and yummy treats to nibble. 

Denison Barbs can tolerate a generous range of parameters but try to stick within the acceptable ranges and avoid any major fluctuations

  • Water temperature: 60°F to 77°F (middle of range is best)
  • pH levels: 6.6 to 7.8
  • Water hardness: 5 to 25 dGH

We highly recommend an accurate water test kit to monitor these parameters. We recommend testing the water more regularly when you first get your Roseline Sharks. Once the tank begins to stabilize and the fish are acclimated, you can reduce the frequency.

Additionally, keep an eye on the pH in your tank. Learn more in our pH lowering guide if you have highly alkaline water and need to bring it down.

What to put in their tank

Plants

As mentioned before, It is a good idea to add live plants to the tank. The idea is to mimic the natural environment. Plants like Java Ferns, and Hornworts are good fits. Java fern is a hardy, low light plant – which is helpful because Roseline Sharks like to uproot their aquarium plants so Java Fern is likely to survive this situation. Additionally, it doesn’t need Co2, fertilizers, or fancy substrates. Hornwort is a bushy, versatile plant that thrives in most environments.

Driftwood

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PIVBY Natural Aquarium Driftwood Assorted Branches Reptile Ornament for Fish Tank Decoration Pack of 3
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What We Like About This Decor

  • Adds to the aesthetic of your tank
  • Provides nooks and crannies for hiding

What We Don’t Like

  • Relatively expensive
  • They may be too large for smaller tanks with other decorations

Rocks

Our Pick
Seiryu Stones for Aquascaping and Aquariums

What We Like

  • They add to the aesthetic of your tank
  • They help provide places for your aquatic critters to hide
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What We Like

  • Good value for large, attractive stones
  • Good assortment of shapes and sizes

What We Don’t Like

  • Stones arrived dusty and in need of cleaning. Be sure to rinse them before use.
  • Will affect the ph/hardness of your water, so be warned if you are planning on incorporating in an established tank

Potential diseases

Roseline Sharks need clean water. They are used to pristine water conditions in fast flowing streams in India, where waste does not accumulate and hardy plants keep the environment clean. Bad water, that is not properly filtered and cleaned, is the source of most diseases that plague Roseline Sharks.

If your Roseline Sharks get sick, you should treat both the illness and evaluate the water. Ammonia and nitrites should be at zero while nitrates can safely be somewhere around 5ppm.

Roseline Sharks don’t suffer from a species-specific disease. However, they can be sensitive to issues like Ich, a disease that covers the fish in tiny white spots. It’s typically a byproduct of stress, which is caused by poor living conditions and dirty water.

To avoid stress-related illness, make sure that you’re using a powerful filtration system and performing regular water changes. You should also vacuum up waste and leftover food

Feeding

Roseline Sharks are omnivores and voracious eaters, meaning they will typically eat most things you offer them.  In the wild, they typically feed on algae, small invertebrates, and insects.

They prefer to eat their food mid-water or from the bottom of the tank. In order to avoid tank contamination, avoid only feeding floating foods. Floating foods will likely be slowly consumed, leading to increase in waste in your tank.

You can supplement the dry food with live and frozen foods. The fish enjoy brine shrimp, daphnia, bloodworms, and spirulina. Sinking pellets like Bug Bites, Repashy, and algae wafers are all great choices. By feeding multiple types of food, you provide a varied diet that better reflects their natural diet and helps avoid the fish getting bored.

Try to feed your Roseline Sharks twice a day. Only provide enough food that they can consume within 2 minutes.

Our Roseline Shark feeding recommendations: 

Our Pick
Omega One Freeze Dried Brine Shrimp
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SAN FRANCISCO BAY Brand Freeze Dried Bloodworms

What we like

·   Great value for the money

·    Nearly all fish types love it!

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Tetra Algae Wafers - Nutritionally Balanced Vegetarian Fish Food

What We Like About This Food

  • Provides necessary nutrients for Clown Plecos
  • Very affordable
  • They sink to the bottom of the tank to appeal to bottom feeders


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Our Pick
Repashy Spawn & Grow Freshwater
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Breeding

Breeding Roseline Sharks typically occurs in commercial settings. It is very rare in home aquarium set-ups. Commercial breeders have elaborate breeder tank set-ups and use artificial hormones, both of which are rarely accessible to home hobbyists.

In reports of home spawnings, most of the time, it appears to be an accident. In all reports, home spawning has only occurred with  groups of at least 15 Roseline Sharks. 

Based on the difficulty of breeding, it is not recommended for the home aquarist. It is difficult and could stress out the fish.

Ideal Roseline Shark Tank Mates

Roseline Sharks are peaceful. They can get along with other non-aggressive tank mates that like to stay active, assuming all of the fish have enough space to swim, hide, and live their lives. 

If kept in tight quarters, however, Roseline Sharks may show aggressive tendencies. Additionally, Roseline Sharks are fast swimmers, so you should avoid putting them with slow swimmers.

It’s best to keep a small group (at least six) of Roseline Sharks together. They do not do well when they’re alone and rely on social interaction to stay healthy.

While it is impossible to provide a complete list of compatible tank mates, here are some potential options:. In general, try to stick to similar-sized fish that can swim fast. Slow fish with delicate fins are not recommended!

Denison Barb / Roseline Shark FAQs

Are Roseline sharks fin nippers?

No, Roseline Sharks are not fin nippers. They’re considered to be a peaceful fish. However, they do need to be kept in groups (minimum size of six) and have sufficient space for swimming. The minimum tank size recommendation is 55 gallons. Additionally, they should be kept with other similar sized fish with similar swimming needs.

How fast do Roseline sharks grow?

Roseline Sharks can grow very quickly with reported growth of 2.5 – 3 inches in the first year of ownership.

Are Denison barbs Hardy?

Yes, Denison Barbs are hardy fish that will thrive in appropriately-sized, planted aquariums. They can tolerate a range of water conditions (temperature, pH etc.) but do need their water to be kept clean. They do best in groups of six or more.

Are Roseline sharks aggressive?

No, Roseline Sharks are not considered to be aggressive. However, they do need to be kept in groups (minimum size of six) and have sufficient space for swimming. The minimum tank size recommendation is 55 gallons. Additionally, they should be kept with other similar sized fish with similar swimming needs.

Reports of aggression are typically with smaller groups (less than 6) Roseline Sharks. Smaller groups have more entrenched hierarchical aggression, which is why larger groups typically do better.

What do Denison barbs eat?

Roseline Sharks are omnivores and voracious eaters.  In the wild, they typically feed on algae, small invertebrates, and insects.

The fish enjoy brine shrimp, daphnia, bloodworms, and spirulina. Sinking pellets like Bug Bites, Repashy, and algae wafers are all great choices. 

How big does a Roseline shark get?

The average size is around six inches in length when fully grown. 

Conclusion

Now that you’ve learned just about all there is to know when it comes to caring for Roseline Sharks, you should be able to decide for yourself if they’re a good fit for your aquarium.

Roseline Sharks get along with most other similarly-sized species and swimmers, but they need plenty of room to swim, places to hide, and fast-flowing currents to mimic their natural river habitats. They’re relatively easy to care for, but can be a challenging match for a beginner.

If you can accommodate their need for large tanks, pristine water, and a large group of friends, they can make beautiful additions to your tank and will entertain you with their flashy colors and athletic swimming..

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