Denison Barb (Roseline Shark): Species Profile and Care Guide

A School of Denison Barb Swimming in a Planted Tank
Dr. Mollie Newton
Published by Dr. Mollie Newton PHD| Senior Editor
Last updated: July 12, 2024
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If you are looking for a fish to bring some bright color to your freshwater aquarium, the denison barb might be an excellent option. This species is not only easy to care for but is also peaceful and showcases stunning hues of red, yellow, and silver. Based on expert advice and evidence-based research, we’ve created this helpful guide on denison barb care to assist you in deciding if they would be a great addition to your aquarium.

Article Summary

  • The Denison Barb, also known as Roseline Shark, is a freshwater fish originating from southwest India.
  • They are considered endangered due to overharvesting for the aquarium trade.
  • Feed them a variety of live and frozen foods such as brine shrimp, daphnia, blood worms, and insect larvae.

Species Overview

Common namesRoseline shark, red line torpedo barbs, red comet barb, bleeding eye barb, Miss Kerala, denison barb
Scientific nameSahyadria denisonii
SpeciesS. denisonii
Size4 in
Lifespan5 years
FamilyCyprindae
GenusSahyadria
DistributionWestern India 
ColorSilver, black, red
DietOmnivore
TemperamentPeaceful
Minimum Tank Size55 gallons
Place in tankMiddle
Care LevelEasy
Breeding Difficult

History and Background

One of the most popular fish in the aquarium trade, the denison barb has a diminishing wild population making it of interest to aquarists and conservationists alike. In 2010, it was added to the IUCN’s red list of threatened species.

What is a denison barb?

Denison barbs are a freshwater fish that have many different names including: roseline sharks, red lined torpedo barb, and Miss Kerala. They hail from the minnows and carp family and are very distantly related to goldfish. Regardless of what you call this fish, its wild populations are rapidly decreasing and is considered an endangered species due to over harvesting after being declared one of the top ornamental fish.

FUN FACT

The nickname “Miss Kerala” comes from the fact that this fish hails from the states of Kerala and Karnataka.

Where did the denison barb come from?

The roseline shark originated in southwest India in the Chaliyar rivers. They are schooling fish and are found in rocky pools, streams, and rivers with thick vegetation along its edges in the western ghats.

FUN FACT

The western ghats are also known as the Sahyadri mountains which is where Sahyadria denisonii gets its name from.

Appearance

Closeup image of the Denison barb seen from the side
Closeup Image of the Denison Barb Seen From the Side

If you’re looking for a great fish featuring a wide variety of colors look no further than denison’s barb.

What do denison barb look like?

The roseline shark is torpedo shaped (hence its other name: red line torpedo barb!). The majority of its body has a silver coloration with a black lateral stripe that runs along the entire length of the roseline sharks body. Slightly above the black line is a red stripe that runs from the nose of the fish to midway.

In addition to the bright red line this fish has black and yellow stripes on its caudal fin as well as red edging along the dorsal fin. Its delicate fins and dorsal fin coloration provides a striking image as these active fish race across your aquarium.

FUN FACT

Some adult fish are known to develop emerald green coloration on their head.

Colors/variations

This species is occasionally found in gold or yellow coloring instead of silver. Additionally, the golden roseline shark has dark brown spots along their body as well as brown fins. Other care requirements are the same as the original variation.

Albino roseline sharks are pale pink, but have white fins and dark eyes.

TIP

Like most other populations the more rare the color variation the more expensive the fish. While you can purchase a single roseline shark for $10-$30 at a pet store, the golden denison barb will cost around $45 per fish. The albino variation is so rare that it is not commonly sold and you would have to contact a breeder regarding price.

How big does a denison barb get?

In its natural habitat roseline sharks can grow up to size of 6 inches, however in a home aquarium they are more likely to grow from 3.5-4.5 inches.

How fast do denison barb grow?

This fish is fairly fast growing and can grow upwards of a half inch every three months until reaching its mature size.

Temperament and Tankmates

beautiful fishes swimming in a planted tropical freshwater aquarium
An Aquarium With Different Fish Species

Choosing great tank mates can be intimidating, especially when you want to ensure that all fish will stay healthy and live a long, happy life.

What fish can live with denison barb?

In a community tank many similar species will go great with the roseline shark. When choosing tank mates, find other species that are of similar size, temperament, and don’t mind sharing their swimming space. While this freshwater species is a schooling species and very active and fast swimmers, they can coexist with other species. We’ve listed a few of our top suggestions below.

  1. Rainbow fish-the metallic sheen on this attractive fish will be sure to capture your attention. There are 20 different species of rainbow fish so be sure to do your research to ensure that size and temperament requirements are met.
  2. Danios-Another common aquarium trade fish, danios are peaceful fish that won’t bother your denison barbs.
  3. Cherry Barb-another barb that’s bright red coloration will complement the red line torpedo barb vibrant stripes. The cherry barb is fairly peaceful and the two will not bother each other.
  4. Rosy Barb-if you’re looking for another brightly colored ornamental fish to add to your tank the rosy barb will make excellent tank mates because of their similar size, life expectancy, and care needs.
  5. Other roseline sharks-as mentioned previously, this fish should be kept in school. A proper shoal size should include at least 6 fish and preferably more.

Tank mates to avoid

The main factors to check for when choosing companions is size, temperament, and bioload. You should find tank mates that are similar in size, are not aggressive, and not put an extreme strain on your aquarium bioload. The following species do not meet one or more of these requirements.

  1. Guppies-unless you are planning on using them for a feeder fish for your roseline shark, we recommend keeping guppies out of your aquarium.
  2. Neon Tetras-while you might be tempted to add neon tetras to your tank to add to the coloration, your roseline sharks will likely mistake these fish for a snack.
  3. African cichlids-a well known bully, African cichlids will likely target your roseline sharks unless they are in a very big school.
  4. Oscars-a large fish that makes large messes. This could potentially prove problematic for the water quality of your roseline shark tank.
  5. Goldfish-while they are peaceful and would likely get along with your roseline sharks you would need extremely large tanks to house the bioloads these two species would produce.
  6. Iridescent Sharks– due to their considerable size difference, there is a risk of the larger Iridescent Sharks seeing the smaller Roseline Sharks as potential prey. Additionally, the active and fast-moving nature of Iridescent Sharks might create stress for the more timid Roseline Sharks, affecting their behavior and well-being.

Tank Requirements

Woman Placing Empty Aquarium On The Table
Woman Placing Empty Aquarium On The Table

While roseline sharks have relatively simple aquarium guidelines they require the quality to be in tip top shape.

Water Parameters

Tank Size>55 gallons
Water TypeFreshwater
Water Temperature68-75
Water pH6.8-7.8
Water Hardness5-25 dGH

Tank setup:

In general, to keep your fish healthy and happy you should try to replicate their natural habitat as closely as possible. For roseline sharks, this would be a warm, tropical streambed with a rocky bottom. Below we’ve listed some great options for how to achieve this.

What kind of substrate to use?

The best substrate for denison barbs is soft sand or fine gravel. You can add larger rock caves or driftwood to the top of this substrate layer to give it a more natural appearance as well as provide hiding spots for your fish.

Do I really need a filter?

It is essential to add a filtration system (there are various types of filters, such as canister, sponge, sand filter, and more) to your home aquarium as roseline sharks require crystal clear or pristine water quality. Without this requirement being met they will likely have a decrease in happiness, health, and their active nature.

Should I have a pump?

While a pump isn’t entirely necessary for roseline sharks it is recommended especially if you have a large aquarium with lots of plant life. The reason being is that live plants will use up a large amount of dissolved oxygen in your tank leaving little to none for you fish. This can cause hypoxia (when no oxygen is available in the water) and kill your fish.

Do I need a Water heater?

It is recommended you keep a reliable water heater in your aquarium to help maintain a stable water temperature range for your roseline sharks. As a tropical fish this species will need water temperatures to remain between 68 and 75 degrees which can be tough to monitor without a water thermometer and heater.

What kind of Lighting to use?

There are no specific lighting conditions that need to be met for the roseline shark. These freshwater fish are active during the day time and will appreciate a regular light cycle of 12-16 hours of darkness and 8-12 hours of light to establish a morning/night schedule.

It is important to establish a light and dark schedule for your fish to help them keep a regular sleep schedule and REM routine.

Can I add Plants to my aquarium?

These fish come from an environment with heavy vegetation and enjoy having plants…

We strongly recommend adding many plant species to your roseline shark aquarium. These fish come from an environment with heavy vegetation and enjoy having live plants to play and hide in. Some recommended species include anubias, marimo moss balls or java fern. Be aware that some roseline sharks will dig up plants so you should choose hardy species or opt for floating plants.

TIP

When adding plants to your tank be sure to leave enough swimming room for your roseline sharks and additional fish. As very active fish they require a large amount of open swimming space.

Diet and Health

Fish Food
Different Types Of Fish Food

When designing a dietary plan for your fish you should focus on feeding them a varied diet of high quality food instead of feeding them lots of low quality food. Quality is better than quantity.

What do denison barb eat?

Roseline sharks are omnivores and their natural diet consists of meaty foods such as smaller fish, invertebrates, and insects as well as some plant matter and algae. You should try to replicate their wild diet as closely as possible in captivity.

What to feed denison barb?

You should feed your roseline shark a variety of live and frozen foods such as brine shrimp, daphnia, blood worms, and insect larvae. Additionally, be sure to provide a varied diet including commercial pellets or flakes and algae wafers or vegetables. Providing a balanced diet will ensure that the roseline sharks coloration stays vibrant and they stay healthy.

We recommend feeding your fish a mix of 80% commercial food, and 20% supplemental live or frozen foods. While it might seem counterintuitive to feed your fish a majority commercial pellet diet, these foods come with vitamins and minerals that are necessary for proper growth and development in your fish.

RECOMMENDATION

For brighter colors use a commercial food with carotenoids.

How often to feed denison barb?

You should aim to feed your roseline sharks twice daily. Because of their high activity level you will need to provide them with extra calories.

How much to feed denison barb?

Use the 3 minute rule to efficiently feed your roseline shark without overfeeding it. When using this method drop a few pieces of food into your fish tank and start a timer. When your fish have eaten all of the food, drop more in and continue this pattern until time is up.

Depending on your tank size you may have to spread out morsels of food throughout the tank so that all fish can access it easily.

Common diseases of denison barb?

There are no species-specific diseases that target roseline sharks, however they are susceptible to other freshwater diseases.

  • Constipation-commonly caused by not receiving enough fiber in their diet, constipation is signified by stringy feces, loss of appetite and bloating. Treatments include feeding your fish nothing but shelled peas for three days, on the fourth day feed them protein and repeat until bowel movements return to normal.
  • Ammonia Poisoning-a common problem in poorly maintained aquariums, ammonia poisoning can prove fatal if not treated in a timely manner. It is signified by irritation of the skin and gills, rapid breathing, lethargy, and loss of appetite. Treatments include immediately lowering ammonia levels by performing a water change, and monitoring water parameters closely.
  • Ich-one of the most dreaded diseases in the aquarium hobby, ich can cause white spots along the body and fins, lethargy, loss of appetite, and the peculiar behavior of rubbing against tank objects. Treatment options include water changes, aquarium salt, or medications such as Ich-X.

How long do denison barb live?

On average this fish species lives for roughly 5 years in ideal tank conditions.

Breeding

School of denison barb swimming through the aquarium plants
School of Denison Barb Swimming In A Planted Aquarium

Unless you are specifically looking for a challenge, we recommend not attempting to breed this species. There is not much research to support breeding these fish in captivity, they are difficult to sex, and it could potentially put them at risk for health issues.

Can you breed a denison barb?

Breeding roseline sharks is difficult in home aquariums, though it will occasionally happen. A majority of this fish species is bred in commercial fish farms where they use hormones to encourage the spawning process.

Additionally, sexing mature specimens is difficult and mostly comes down to estimating sizes (female fish are usually larger).

How to breed a denison barb? 

Little is known on how to breed roseline sharks in captivity other than commercial breeders use soft acidic water and have soft, fine sand for the eggs to be laid on.

For the most part we recommend not attempting to breed your roseline sharks as changing their conditions to induce spawning could cause them stress and decrease their quality of life.

FAQS

Are Denison barbs aggressive?

No, roseline sharks are generally peaceful fish species and will mostly keep to their school. When you first introduce them to their schooling companions you might notice some initial fin nipping or other normally aggressive behaviors. This is the fish trying to establish a hierarchy and is completely normal. However, if aggressive behavior continues after a week and seems to target one or two specific fish, remove the offender to prevent bullying.

Will Denison barbs eat other fish?

If your aquarium has lots of small fish that could easily fit in a roseline shark mouth then there is a chance they will mistake them for a snack. Overall, the roseline shark eating tank companions is not a large concern.

Do Denison barbs jump?

Yes, it is recommended that you keep a tight fitting lid on your aquarium, only removing it to drop food in or quickly clean to avoid any of your roseline sharks from escaping.

Do Denison barbs eat plants?

You might notice your roseline sharks nibbling at a plant or two but it is not common for them to target plants for consumption. However, they are omnivores, and if you do see them snacking on a plant leaf or two they might not be receiving enough vegetable matter from their diet.

TIP

If you see your barb nibbling on the edge of a leaf it is more likely they are snacking on the algae that has grown on the leaf.

Is the denison barb for you?

While the denison barb is a niche species it is one of our favorites for its adaptability into most tropical freshwater tanks. Additionally, it is a great beginner fish for hobbyists that are starting to get more serious about the aquarium world.

Conclusion

In conclusion, while the Sahyadria denisonii goes by many names it is beloved by all aquarists who keep it due to its activeness, bright colors, and ability to get along with the vast majority of companions.

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