If you’ve been perusing online, thinking about what you might next like to add to your fish aquarium, and saw Rainbow Shark, we would not be surprised that you stopped at this article.
However, if you’re looking for an actual rainbow-colored shark, be advised straight off the bat that this article will detail a species of fish that is neither of these things.
Now that’s settled, we begin a discussion about a small tropical freshwater fish (that’s right – fish, not shark) native to the river systems of Thailand and Southeast Asia.
They may also be referred to as Red Fin Sharks, Ruby Sharks, Rainbow Sharkminnows, and Whitetail Sharkminnows (all slightly misleading), but nevertheless, they are members of the Cyprinidae family and not Chondrichthyes.
Colorful though they are, rainbows they are not. And while they also possess a well-known territorial attitude, they remain far from being sharks. They got the name shark in their common name purely because of their stiff, upright dorsal fin reminiscent of the sharks we know and love. Reality dictates that they are from the same family as the humble Goldfish, Loach, and Common Carp.
These fish are a tale of two halves and are not for the inexperienced, but they do make a great addition for communities of larger tank enthusiasts who might want to brag about owning a ‘shark’ by name. Nobody has to know, and we aren’t telling.
Rainbow Shark Behavior
Classified as semi-aggressive fish, Rainbow Sharks are active swimmers and like open water to do so in. Primarily they will settle on the bottom third of your tank but can be occasionally seen on the middle or top layers.
This makes them ideal for similarly sized species who like to occupy the mid to upper sections of your tank while the Rainbow Shark cleans algae and leftovers. They’re great little tank cleaners for that reason.
We already mentioned that they can be territorial, so for this reason, you would want to avoid having them with other bottom dwellers as they will let loose their attitude in an attempt to dominate. Bullying behaviors can be observed when this is the case, and you can expect infighting as a result.
You will really not want to include more than one male of this species in a tank environment as it will inevitably end up in disruptive disputes on a regular basis. Injury or even death is likely to occur, so it’s best to keep it to one.
Interestingly, it’s almost impossible to sex juveniles, so keeping your gender ratio correct might involve buying a more mature specimen so you can be certain.
These fish also love to hide in their tank, particularly as juveniles, so you will need to ensure that they have plenty of spaces to duck out of the limelight as they see fit.
They tend to be loner fish who like a solitary existence in their tank layer, so bear that in mind when considering having one.
Rainbow Shark Lifespan
You can expect to have a Rainbow Shark for anywhere from 5-8 years if kept well, although they don’t reach their full size until about 2 – 3 years of age.
We will discuss more on tank requirements a little later in this article.
Rainbow Shark Appearance
We’ve already mentioned that these fish have a shark-like structural quality to them in both body shape and dorsal fin.
Predominantly dark grey on the body, they then have brilliant red, rayed fins that make for a sharp standout appearance in the tank.
They possess slightly flattened heads coupled with large eyes and what looks like catfish-type barbels on their mouths which is a sensory organ.
These fish have a similar type of skin to catfish and are not scaled, so they can be susceptible to injuries and wounds if you aren’t careful.
At full maturity, they can reach about 6 inches in length, although cases are reported of up to 8 inches in length, and males are usually slimmer than females.
Another point to note here is the existence of the Albino Rainbow Shark.
Yes, this sounds even more complicated. Still not a rainbow of color, still not a shark. But instead of dark grey body color, these fish are yellowy-white with vibrant orange or red fins, so they look equally outstanding in an aquarium and are rather eye-catching.
The world of fish keeping is full of surprises and wonder, which keeps enthusiasts coming back for more. You can always learn something new, and the water systems of our planet are so vast much is unexplored.
Let’s take a look at tank requirements for a happy Rainbow.
Rainbow Shark Habitat And Tank Requirements
These Asian fish enjoy fast-moving waters, lots of places to hide, and plenty of vegetation. This is a fish that even likes a wavemaker, but do ensure that the rest of your tank population are equally agreeable to these conditions.
An abundance of plant life will help keep your fish distracted from potential conflict, provide areas to hide, and better filtration to keep your tank clean and healthy.
Let’s look at some specifics that are needed.
Tank Conditions
Air stones and a wavemaker will offer you the additional water flow you need to keep your Rainbow Shark happy.
Being river basin fish, you will want to keep the flow unidirectional like a current and not a bubbling air cloud.
Great decor such as hollowed-out caves, rocks, treated driftwood pieces, and plants are what you need to aim for to keep these bottom dwellers happy and healthy.
In terms of substrate, you’ll ideally want sand, which mimics their natural habitat. Because of their skin type of body surface, jagged gravel that works well with scales should be avoided. In fact, any sharp decoration should be avoided.
Water conditions should be noted, tested regularly, and maintained as follows:
- pH of 6.5 – 7.5
- Water hardness 5 – 11 dGH
- Temperature between 75 – 81ºF ( 24 – 27ºC)
- Lighting should be kept at a medium level
Tank Size
The minimum tank size needed is 55 gallons for a single Rainbow Shark, but expect to have closer to 125 gallons if you’re aiming for 2 or 3.
We do not recommend housing more than a single Rainbow Shark purely because of conflict with territorial boundaries. You should really only consider it if you are intent on breeding but more on that issue a little later.
These fish enjoy patrolling their territory rather fiercely, and because they enjoy active swimming, you should aim for a long rectangular tank. This will allow them enough horizontal space to give them bursts of energy, reduce aggression with any tank mates present, and avoid feeling cramped.
Choosing Tank Mates For Rainbow Sharks
We indicated earlier that you should aim to have community fish that occupy the mid or upper levels of your tank for best relations with a Rainbow Shark.
As your Rainbow Shark will defend and actively patrol their turf in the bottom layer of the tank, you should ideally have a variety of hidey-holes for them to occupy available to keep them on an even keel.
They don’t tend to initiate aggression with other fish that don’t resemble Rainbow Sharks, but they do feel miffed if Cichlids or Catfish who want to take their turf decide to get involved.
Here are your best bets if you wish to have other fish alongside a Rainbow Shark:
- Gouramis
- Rainbowfish
- Barbs
- Danios
- Rasboras
- Snails
- Loaches
- Plecos
Avoid anything like Bala Sharks, Cichlids, Catfish, or Red Tail Sharks.
Feeding Rainbow Sharks
Rainbow Sharks are mostly omnivores but will consume plenty of excess algae in your tank along with meaty pieces and larvae.
Brinefish are ideal for protein, along with frozen bloodworms, tubifex, dwarf crustaceans, and other aquatic insects.
For variety, you can chop up vegetables like cucumber, spinach, or raw peas for them to graze on. But just ensure that you keep the floor of your tank clean to avoid fouling of water.
These fish are unfussy and are happy to eat just about anything you put in front of them at the bottom of the tank. Feel free to include items that are flaked, pelleted, frozen, tableted, or live. Just make sure that you keep mixing up their diet with a wide variety of food sources.
Rainbow Shark Common Health Issues
This is a hardy freshwater fish, so luckily, they don’t require a lot of outlook for diseases specific to the species.
However, like most freshwater fish, they remain susceptible to diseases such as Ich, various types of fungus, Skin Flukes as well as disorders of the Swim Bladder.
Keeping water quality pristine will help your fish retain optimum health. Regular water changes will keep this bottom-dwelling fish with less chance of getting ill from poo condition in the tank.
How To Breed Rainbow Sharks
Rainbow Sharks are amongst the larger-sized freshwater fish most people would consider having in a home aquarium.
Although not easy to sex these fish as juveniles, eventually, the telltale black lines on the tail fins of males will become apparent.
There isn’t a lot we can discuss when it comes to breeding Rainbow Sharks, however, because it’s incredibly difficult to do in captivity. It would require expensive considerations that are due to the space needed and the aggressiveness of these fish in the first place.
If you are still interested in hearing about how they breed, however, the female will lay eggs once she has decided on a mate. He will then fertilize them, and it can take up to a week before any fry will hatch.
Breeding in the wild will usually happen between October or November.
Any Rainbow Sharks you are likely to find to buy have either been wild-caught or are from commercial farms equipped with the vast amounts of space needed from Southeast Asia.
Conclusion
Rainbow Sharks are interesting to have in your tank, provided you have planned your community with some forethought. Having the right tank size allowing them to feel like they are ‘king of their castle’ is a surefire way to reduce aggressive behavior.
They provide a lot of enjoyment for owners to watch as active swimmers and are notable contributors to tank cleanliness for a medium-sized bottom dweller.
It’s worth reiterating again that they should be kept solo (in terms of no other Rainbow Sharks in the same tank) if you do decide to purchase one. Asking a captive Rainbow to tolerate others of its kind, or even ones who just look similar, is asking for trouble in the tank.
They remain a rewarding fish to keep if you’re considering leveling up your aquarium experience, and although not difficult to care for, they aren’t for novices either. Despite their reputation, if you’ve chosen carefully, they will not cause too much disruption in your tank.
