Denison barbs are active fish that do well if kept in schools of at least 6 or more. They require large tanks to thrive that are 55 gallons or more.
Their peculiar features earned them worldwide popularity, which unfortunately caused a serious drop in wild reserves. As a result, Denison barbs have been declared an endangered species and they’re on the Red List of the International Union for Conservation of Nature (IUCN).
If you want to learn more about them, read this Denison barb fish profile in which I discuss the keeping, feeding and breeding requirements of the Denison barb fish.
Introduction
Because of their torpedo shaped bodies and striking colors, Aquarama, the international ornamental fish exhibition, named the Denison barb one of the top ten new fish species.
This launched them into popularity, which caused a serious trend of overexploitation for the aquarium trade, leading to a significant drop of Denison barb populations in the wild.
Native to Southern India, the Denison barb is also called the Red Lined Torpedo Barb because of a bright red line that runs from the nose all the way through the eyes and the mid-section of the fish.
The edge of the dorsal fin is also red, while the caudal fins feature black and yellow stripes. As the fish matures, a greenish hue starts to appear of their head.
This red line is beautifully contrasted by a black line that runs the entire length of the fish from head to toe. These colors are all the more striking because of the otherwise silvery body of the fish.
Some varieties that resulted from selective breeding in captivity lack the black stripe and have developed a golden color.
Denison barbs reach 6 inches (15 cm) in adulthood and require large tanks that offer them plenty of swimming space. Their pair of barberls help them in locating prey.
While overfishing as a result of high demand has been one of the main reasons why the Denison barb population plummeted in the wild, pollution and deforestation are also to blame.
Here is a video of denison barb fish:
Denison Barb Water Requirements
In the wild, denisons can be found in highly oxygenated water that’s heavily vegetated and rocky. Recreating the water conditions that are favorable for this fish is not difficult but be advised that a large tank is a must.
1. Tank Size
When setting up an aquarium for their fish, many beginner aquarists don’t take into account the size these fish can reach in adulthood.
A small tank is no good fit for these fish, so get a big enough tank from the get-go. A 55 gallon tank is a must the very minimum you should pick for them.
Hiding places such as driftwood and rock caves are appreciated additions to the tank as so are some plants.
Live plants that are easily uprooted are not recommended, therefore, go for Anubias plants, which are hardier, just make sure they’re well anchored.
A power head or a spray bar is also necessary to ensure water movement.
2. Water Parameters
While the Denison barb is relatively easy to care for, I usually don’t recommend them for beginners.
There are two reasons for this:
- These are semi-aggressive fish that you need to keep an eye on if you plan on keeping them in a community tank
- Pristine water conditions must be met, something that beginners may not be able to accomplish that easily.
The temperature in the tank should be around 60–77 degrees Fahrenheit, which is a bit lower than the typical tropical set-up. Water pH should range from 6.8 to 7.8, that is, slightly acidic to slightly alkaline. Hardness should be up to 25 dGH.
Regularly cleaning the tank is absolutely necessary since these fish don’t tolerate high toxin levels or high levels of organic matter.
Denison Barb Tank Mates
For starters, Denison barb fish should be kept in schools of 6 or more to make them feel comfortable and potentially temper their aggressive tendencies.
Because they can be aggressive in a community tank, make sure you house them with species that are similarly sized or larger.
Offering them plenty of swimming space is another way to curb their potential behavioral issues, therefore, tanks below 55 gallons are not suitable for these fish.
Good tank mates that you can consider for this fish include other barb fish, larger-sized tetras, most cichlids, and rainbows are all compatible with Denison barbs.
With plenty of space, good tank mates, and a school of at least 6, you won’t encounter any aggressive tendencies.
Denison Barb Diet
Denisons are omnivorous fish that enjoy variety in their meals. They can be fed a mix of meaty foods like shrimp, daphnia, cyclops, and blood worms either as a frozen, freeze-dried or live food.
Vegetable matter should also not be absent from their diet and you can add fresh vegetables, algae and spirulina wafers to complete they diet.
Therefore, they’ll accept most foods, so feeding them a balanced and nutritious diet is easily possible.
Make sure you don’t overfeed them because of potential water fouling that can happen when fish eat more and produce more waste.
Denison Barb Breeding
Denison Barb Breeding – Source
After the Denison barb fish gained popularity, as much as half of India’s ornamental fish exports were Denison barbs.
Overfishing coupled with environmental destruction have made conservation efforts necessary. Thus, India introduced periods when Denison barb collection is prohibited.
Commercial breeding programs in Southeast Asia and Eastern Europe have also been introduced. Despite these efforts, the fish continues to remain on the endangered species’ list.
If you’re wondering if you could breed Denison barbs in home aquariums, you may be disappointed to find out that there are quite difficult to breed.
There aren’t many reports of spawning that occurred in home aquariums, however, commercial breeding programs have been more successful.
In the wild, the breeding season for Denison barbs is November to March. A captive breeding program conducted at the Kerala University of Fisheries and Ocean Studies have experimented with a breeding protocol and successfully bred three Denison barb pairs.
The scientists at Kerala University have recreated the natural conditions of the waters inhabited by Denison barbs and taken the following steps to breed them:
Recreating the Natural Habitat
Water for the artificial habitat was sourced from the natural habitat of the fish and so were sand, rocks, plants and sediments. Water was allowed to flow continuously through the artificial habitat by gravitational force.
Conditioning
Collected broodstock were fed protein-rich artificial food, bloodworms, earthworms and were segregated based on sex and reared in glass aquariums.
Because of a lack of sexual dimorphism, determining the gender of Denison barbs is quite difficult.
One physical trait that is different in female Denison barbs is that they have a slightly wider body when they reach sexual maturity.
A the most reliable way to tell the gender of a Denison barb is inspecting the genital openings. A ripe female will extrude eggs under gentle abdominal pressure, while the male can be identified by the flow of milt in the genital area.
Breeding experiments were conducted in the period coinciding with natural spawning of these fish in nature.
Spawning was induced by injecting the fish with a single dose of ovaprim (a hormone to stimulate spawning).
Fertilizing Eggs
Fish were first anesthetized to reduce handling stress, which could cause their death. Male and female were kept together in 2:1 ratio in a glass tank of 40 gallons, where continuous aeration was provided.
Since induced broodfishes did not release eggs or milt on their own, both males and females were stripped, and eggs were dry fertilized using collected milt after a latency period of 10-12 h. Fertilized eggs are spherical, orange-brown and adhesive.
After fertilization, the eggs were removed and placed into a gently aerated tank with water parameters monitored weekly.
Hatching Eggs
Eggs hatched 36 hours after fertilization at 81.5 F degrees. In larval stage the yolk sac remained for 3-4 days, after which Denison barbs took external feeding.
With this method, fertilization rate was 86%, while hatching rate was at 85%. The study is from 2015 and it’s the first ever successful captive breeding of Denison barbs.
As you can see, breeding these fish in captivity requires quite a bit of “medical intervention” and unlike other barbs species that will breed naturally even in captivity, Denison barbs require hormonally induced breeding.
Therefore, it’s highly unlikely that aquarists hoping to breed this species in their home aquariums will succeed.
Final Notes
Overexploitation for the aquarium trade can have long-lasting negative consequences on the viability and sustainability of natural sources, therefore, it’s important to limit the collection of these fish and take measures to preserve them in their natural habitat.
Hopefully, successful captive breeding programs like the ones conducted by the scientists at Kerala University, along with conservation measures adopted in the region, will help prevent the Denison barb from becoming extinct.
I hope you’ve found my article on Denison barbs informative and I hope I have answered your questions about this species.
Featured Image:https://commons.wikimedia.org/wiki/File:Akwa18_puntius2.jpg
