The Denison barb, also known as Denison’s barb, Miss Kerala, Red-Line Torpedo barb, or Roseline Shark, is a newer Indian species to the fish collecting world that is usually kept for display in small schools.

First imported in approximately 1996, the Denison barb is an attractive schooling fish that has become popular with fish keepers but is also a threatened species in India.

The Denison Barb is somewhat unique in that exports of wild fish have ceased, but local commercial breeding of this species is thriving. Availability is more dependent on the supply chain of bred fish than the actual demand for the species, which is quite high.

Denison Barb Stats

Listed tank sizes are the minimum
Size: May grow up to 6 inches (15cm)
Tank: 55 gal minimum
Strata: Bottom, Middle, Top
PH: 6.5-7.5
Hardness: 5° – 25° dH
Temperature: 59°F to 77°F (15°-20° C)

Classification

Order: Cypriniformes
Family: Cyprinidae
Genus: Puntius
Species: denisonii

Origin and Appearance

Found in southwest India, the Denison barb is endemic to four specific regions in a 3,000 square mile area including the Achenkovil, Pamba, and Chaliyar rivers. The species prefers fast-moving water, rocky pools, and eddies with thick vegetation for them to hide in.

Aquarium keepers like the Denison barb or Roseline barb for its active nature and beautiful coloring. In body shape, the Denison barb is slender and shaped much like a shark with a rounded belly and soft, translucent fins.

The Denison barb or Roseline shark size can reach up to 6 inches long but except in the largest aquariums generally do not get longer than 3 inches. Well kept, the Denison barb lifespan is up to 5 years.

The coloration of the Denison barb is striking. Against a body of silver or gold, there is a half-length bright red stripe underlined by a black stripe running the length of the fish. The dorsal fin is a bright red, matching the stripe. Its tail is a deep shade of blue, almost black, with yellow bars on the top and bottom lobes.

Denison Barb Care Guide

The Denison Barb is a schooling species that uses all levels of an aquarium. This provides a great deal of flexibility in setting up a habitat and caring for your fish. They are active and need a tank that will allow them plenty of swimming room but also a variety of habitats to explore. An aquarium of 55 gallons in a horizontal format is the minimum size for keeping a group of 6 Denison barb. If you want to create larger schools a much larger aquarium is needed.

As their native habitat is cool, running water, the Rose Lined shark or Denison barb does best in water that is flowing and high in oxygen. Oxygen content and water movement can be provided with a powerful filtration system with a water pump.

Denison Barbs are sensitive to water quality and changes. The water should be tested, and the aquarium cleaned weekly. Maintain the water pH between 6.5-7.5 and the hardness in the range of 5 – 25 dH. Waste should not be allowed to accumulate in the aquarium. Either house tank mates that will keep the bottom clean or vacuum up food and fish waste regularly.

The ideal temperature range is 59°F to 77°F (15°-20° C). If housing Denison barb with tank mates that need water on the warmer side an aquarium heater is recommended to keep the tank towards the high end of their temperature range.

If water quality falls outside these parameters, your fish can get sick. Denison Barbs are susceptible to Ich, which can weaken and kill the fish. Ich is treatable but can also spread rapidly.

The signs of Ich are fuzzy spots on the fish body, sluggish and erratic behavior. If your fish develop Ich, isolate them into another tank. The main tank should be cleaned and water temperature and quality-adjusted.

Designing a habitat for Denison barb allows you to be creative. The species needs variety. If you put them in a completely open water tank, they will become sluggish and lose their coloration.

Beginning with standard coral sand or aquarium gravel substrate, try adding plants in groupings across the tank. The plants should be rooted or anchored firmly in the substrate as the Denison barb might try to uproot them.

Most plant species will do well for a barb-friendly aquarium. Pothos is good for creating environments with plants in and around the aquarium. It should be used sparingly for Denison barb can be a leaper and a secure tank lid is highly recommended.

Anubias and the many Java Fern varieties are good choices for all tanks. Amazon fern can be used for very large tanks.

Vegetated aquariums do best with more light. Having your aquarium on a day/night timer will keep the Denison barb and plants happy and provide active time for all species in the aquarium.

Often fern species come attached to driftwood. You can add additional pieces of driftwood, rock, and sculpture to provide the look you want and homes for the tank mates you are considering.

Tank Mates

Denison barb or Roseline Shark compatibility is based on several factors including the number of fish you have in the aquarium, how you have laid out the tank and how active the species is.

They are mostly peaceful but highly active. You will often see them swimming rapidly in groups. In crowded tanks, they can become aggressive and will bully smaller, less active species.

They can be fin nippers so fish with flowing fins should not be included in a Denison barb aquarium.

Ideally keep them with active fish of similar size, but they will work well in most community set-ups providing extreme size differences and no overly aggressive fish are present.

Ideal tank mates include:

  1. Cherry Barb: The Cherry Barb is an attractive, bright-red fish that is similar in size and temperament. It is considered a threatened species in the wild but is often bred in captivity. Most of the fish you will buy will be commercially raised. They live for 5 to 7 years.
  2. Pearl Gourami: The Pearl Gourami is a 2-to-3-inch fish with distinct white, pearl-like markings. They are of similar temperament and like the same types of vegetative habitat. They are an ideal choice especially when you are kitting out an aquarium of over 30 gallons. Pearl Gourami fish do best in groups of 6 or so balanced heavily toward female fish.
  3. Cockatoo Dwarf Cichlid: This smaller, peaceful member of the species makes a good tank mate. It is very attractive and easy mannered with a temperature and water quality tolerance compatible with Denison barb.
  4. Celestial Pearl Danio: The Celestial Pearl Danio has been popular in the aquarium world since the early 2000s when they were first bred in captivity. They are bright, colorful tank mates with the same water preferences and tolerances.
  5. Rosy Barb: Rosy barbs are attractive, easy to care for, and readily available. They are a popular choice as tank mates for their color and peaceful nature. Does best in small groupings.
  6. Desert Rainbowfish: This Australian species is a peaceful, top dweller with the same tolerance for water temperatures and quality. It does very well in small schools and vegetated aquariums.
  7. Tiger Barb: Hailing from Borneo and Sumatra, the Tiger Barb is a similarly sized fish that does well in mixed tank environments. It is peaceful and an omnivore.
  8. Cyprinids: This family of fish contains most of the carp species. Its smaller members tend to live in the bottom layer of tanks and are omnivores.
  9. Kribensis Cichlid: Originally an African species, the Kribensis Cichlid is very hardy and adaptable. The species averages about 4 inches long and will live to 5 years. It does well in small groups and likes to find hiding spots in the aquarium. This species can be a fin nipper.
  10. Odessa Barb: The Odessa barb is a species that has become a popular tank mate because of its hardiness, peaceful nature, and beautiful red and yellow coloring. They are a good choice for novice fish keepers.
  11. Rosy Tetra: The Rosy Tetra, as well as many other species of Tetra, thrive in the same water conditions as Honey Gourami. They are peaceful but may engage in fin nipping when stressed or in overcrowded tanks.
  12. Guppy: There are many varieties of guppy that make great tank mates for Denison barb. What they all have in common is that they are peaceful fish that are not too small and get along well with everything that will not eat them. Some of the more ornamental varieties will look great in your aquarium.
  13. Plecos: Plecos are beautiful little bottom-dwellers that are popular for their ability to help keep an aquarium clean. They are omnivores and will make short work of sinking food. They are peaceful but solitary. Don’t put more than one in standard size aquariums.
  14. Corydoras: Like Plecos, Corydoras are a variety of bottom-feeding catfish commonly placed in tropical freshwater aquariums. They grow up to 4 inches in size and are peaceful omnivores.
  15. Cardinal Tetra: Cardinal Tetras make great neighbors with many kinds of similarly gentle species. A small school of Cardinal Tetra adds beauty to any aquarium. Always a great choice. Add them in groups of 10.
  16. Neon Tetra: Another great tank mate choice. Adding them in groups of 10, same as Cardinal Tetra, per 20-gallon tanks will give you an ever-moving, shimmering display.
  17. Green Neon Tetra: If you want to keep a brightly colored aquarium, the Green Neon Tetra is a fun tank mate to consider. Similar in size and appearance to the Neon Tetra, the Green Neon Tetra, as its name implies, has a beautiful streak of neon green along its sides.
  18. Snails: Snails are slow and peaceful and will help keep the aquarium clean.

Breeding

In the mid-2000s the Denison barb was in danger of being wiped out from its native habitat by over-harvesting. Thanks to the efforts of knowledgeable amateur collectors and few universities, a path to successful captivity reproduction were developed.

The process to breed them is extremely complex and not suited for most home hobbyists.

One of the major difficulties is sexing adult Denison barb. It is very difficult to tell them apart when they are not in spawning mode. Another is timing. In the wild, the fish will breed from October through December. This timing varies from river to river within their home range.

The induced breed process involves water chemistry manipulation, advanced feeding schedules, and sedation of fishes. It is not recommended to try at home.

For more information on Denison barb breeding, you can contact the Indian state of Kerala University of Fisheries and Ocean Studies at http://kufos.ac.in/.

Diet

Denison barb may be difficult to breed in captivity, but they are very easy to feed. They are omnivores and will readily dine on whatever you offer them. As with similar species, a variety of foods is recommended to keep them from turning off one food type.

For a successful feeding regimen try alternating these foods:

  • Live or freeze-dried brine shrimp
  • Live or freeze-dried blood worms
  • Shredded vegetables such as squash or zucchini
  • Chopped earthworms

Denison barb will chase sinking food all the way to the bottom and can become aggressive during feeding time. If this happens in your aquarium, focus their food variety on floating or slow-sinking foods so they have time to consume it before it reaches the mid or lower levels. Feeding two small meals a day is a good schedule that will also help them stay entertained. A varied diet makes for a happy Denison barb.

Summary

  • Denison Barb is a threatened species that is available to fish keepers as commercially raised fish.
  • They are brightly colored, attractive fish with a penchant for being highly active.
  • The Denison Barb is sensitive to water temperature and quality changes.
  • Sahyadria denisonii is best kept in groups of 6 per 55-gallon aquarium. Large schools require very large aquariums.
  • Decorate the tank with mixes of vegetation, driftwood, and other structure for them to explore.
  • They do best with peaceful tankmates of similar size.
  • Try to select tankmates that keep to the middle or lower levels of the aquarium to help minimize conflicts during feeding times.
  • Denison barb are omnivores. A good, varied diet will help them live longer and stay healthy.

Denison barbs are an ideal choice for keepers who want a large aquarium of lively, colorful fish. You can also take pride in supporting a threatened species by not keeping fish that have been taken from the wild.

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