Rainbow Sharks, also known as Red Fin Sharks or Ruby Sharks, are small tropical freshwater fish native to Thailand.
They are known for their vibrant red fins and being territorial.
If you’re looking to add some color and attitude to your aquarium this may just be the fish for you.
In this article we will discuss how to care for them, dietary needs, tank mates/compatibility, breeding and much more.
Let’s start with a quick summary before we move on to discuss their appearance and compatibility with other fish.
Care Level: Easy/Moderate
Color Form: Gray, Red
Lifespan: 5-8 Years
Size: Up to 6″
Minimum Tank Size: 50 Gallons
Tank Set-Up: Tropical Freshwater: Rocks, Caves or Plants
Compatibility: Moderate. Get along with many other freshwater fish species
Overview of Rainbow Shark
The Rainbow Shark is a tropical freshwater cyprinid that is somewhat difficult to keep. It would be suitable for fish keepers who have a few years of experience and are looking to expand their aquarium.
They are known for their territorial nature and bright vibrant red fins.
Originating from the warm rivers of Southeast Asia, they were given the affectionate common name of Rainbow Shark, due to their upright dorsal fin which gives them the appearance of a shark.
You should expect your Rainbow Shark to grow up to 6 inches in length and have a lifespan of 5-8 years.
In terms of cost you should be looking to spend no more than $3 per fish, and they are readily available all year round.
If you do intend to keep Rainbow Sharks you should make sure your aquarium has plenty of hiding places for them as this helps to reduce their territorial behavior.
A thorough discussion of sharks here Sharkright.com
Rainbow Sharks’ Appearance
The Rainbow Shark is a dark gray fish with vibrant red/orange fins.
They have a long, flat stomach with a pointed snout and an upright dorsal fin. It’s this fin which gives them the appearance of a shark.
The Rainbow Shark is a small fish which you should expect to grow up to around 6 inches when fully matured.
It is not possible to identify their gender whilst they are juveniles. You have to wait until they are sexually matured.
Once sexually matured females will have thicker bodies, and males will develop small black lines on the tail fin. Whilst males will be thinner, they will generally have brighter colorations.
A common variety of the Rainbow Shark is the Albino Rainbow Shark.
Whilst the Albino Rainbow Shark maintains the red/orange fins, its body is white. It will grow to a similar size as a traditional Rainbow Shark and matches several of their characteristics including being territorial.
The Rainbow Shark is a territorial fish which can cause certain behavioral problems such as aggression and dominance.
This generally happens as they mature. As juveniles they are timid and will spend large periods of their time hiding.
They are active swimmers and tend to spend most of their time dwelling at the bottom of the tank. Due to them being bottom-dwellers, they are known as aquarium cleaners as they will eat the algae growing on the bottom of the tank.
You should make sure your aquarium is long and has plenty of space for your Rainbow Shark to swim on the same level.
Whilst they are peaceful with fish that dwell in higher water, they are known for fighting with bottom dwelling fish, including their own kind.
Such behavior can include biting, chasing and head-and-tail butting.
You can attempt to reduce this behavior by ensuring they are placed in a large aquarium, with a low fish to water ratio. You should also ensure they have lots of hiding places, such as caves, tunnels and other hollowed décor.
Finally, whilst they aren’t renowned for jumping, it isn’t unheard of. For this reason you should make sure your lid is well fitted to prevent them jumping out of your aquarium. Jumping generally occurs when they are first placed in the aquarium.
Habitat and Tank Requirements
As mentioned in the overview section, Rainbow Sharks are tropical freshwater fish that originate from Thailand.
They are active swimmers so adults should not be kept in aquariums smaller than 50 gallons. The aquarium should also have plenty of horizontal space. If the aquarium is too short in length it will encourage them to become more territorial and aggressive.
If you plan on keeping multiple Rainbow Sharks then you should use at least a six foot long, 125 gallon tank (however we don’t recommend keeping more than one Rainbow Shark per aquarium; more on this later).
Due to the Rainbow Shark’s territorial nature, you should ensure your aquarium has lots of hiding places for them. Think caves, treated driftwood and rocks.
Dense vegetation and plants also work. Plants can be used to keep them distracted so it will reduce conflict and also help prevent algae.
As for substrate, they are best suited to sand, as this is what is found in their native Thai rivers. Be careful if you intend to use gravel because the sharp edges can cut them. If you do decide to use gravel make sure it’s very fine.
Finally, you should make sure your aquarium lid is fitted well, they are can jump!
You should keep it within the follow parameters: 75°F to 81°F, pH level 6.5-7.5 and a water hardness of 5 to 11 DH.
With Rainbow Sharks you need to keep the pH level stable. Sudden changes in the pH level can cause them to become more aggressive than usual.
Lighting should be kept at a medium level, and the water movement should be moderate.
Is the Rainbow Shark Right For Your Aquarium? (Summary)
The Rainbow Shark would make a great addition to your community providing they aren’t kept with the same, or similar looking fish.
Whilst they are known for being territorial, providing you give them a suitable aquarium environment and match them with the appropriate tank mate(s), you shouldn’t have too many problems with them.
They are a beautiful fish and an active swimmer, so will provide you with enjoyment when watching them in an aquarium.
They are good eaters and will eat a variety of food forms including pellets, flakes and frozen meat.
If you are planning to keep Rainbow Sharks, you should also make sure that you’ve got some fishkeeping experience already, as these fish generally aren’t for beginners.