Aquarium Fish

Rainbow Shark Fish

The Rainbow Shark is a freshwater cyprinid that comes from Thailand and may not be a good choice for a community tank. This fish likes to stake out their own territory in the tank. This territory can be in the form of small caves, rocks and even plants. They will become aggressive with smaller fish that invade this territory. Only keep one of them in your tank because they will not tolerate another Rainbow or Red Tail Sharks in the same tank. They may exist together for awhile, but one will end up chasing the other relentlessly until the other succumbs. You may also see an albino variety that is sometimes available at your local fish store.

They will eat most fish food including flakes, pellets and frozen foods. They will eat algae wafers as well.

Breeding this freshwater shark is rare in the home aquarium. This is most likely because of their intolerance of each other in the small confines of the home aquarium.

You will need a good tight fitting hood with no escape points because thy have been known to jump out of the tank.


Rainbow Shark


Fish Care Details

Scientific Name : Epalzeorhynchos frenatus

Common Names : Red Fin Shark, Red Shark, Ruby Shark, Albino

Care Level : Easy

Size : 6 inches (15 cm)

pH : 6.5 - 7.5

Temperature : 75°F - 80°F (24°C - 27°C)

Lifespan : 5 - 8 years.

Origin / Habitat : Thailand, Indonesia

Temperament / Behavior : This fish can become aggressive with other, smaller fish in your tank that invade its territory. They will fight with the Red Tail Shark. Provide plenty of hiding places (caves, rocks and plants)

Breeding : Because they will fight with other rainbows, breeding them in the home aquarium is rare.

Aquarium Size : 55 gallon (208 liters)

Tank mates : Because of their temperament it is a good idea to house them with similar sized fish. Do not keep with other Rainbow sharks and Red Tail Sharks

Fish Disease : Freshwater Fish Disease

Diet / Foods : An herbivore - provide a varied diet with algae wafers, pellet food and frozen food.

Tank Region : Mostly bottom to middle

Gender : On males, the anal fin is outlined in black

Fish Lore Forum : Rainbow Shark Forum

References :


From: Joe - food and tank recommendation
Based on my prior experiences I suggest you do not feed them algae wafers because they usually do not eat them. Secondly, make sure the tank's pH is stable. Sometimes it may cause the shark to become hyper and become more hostile. In some other cases the wrong pH might make them seem lethargic and not eat.

From: Katie - Shark jumps to his demise
I have had my rainbow for about 6-7 months now. He was in a tank with some danios, a few other fish and 2 dwarf frogs. He was fine until about a week ago when he started getting really aggressive with the other fish and actually attacked one of the frogs to death. I took him out of the tank and put him in a separate bowl for the night and was going to take him back to the store for a trade-in. Well, he did not survive the night as he jumped out of the bowl and I found him dead and crusted on the kitchen floor. Watch out! These fish can become vicious out of no where!

From: Megan
I have had my shark for about 14 months now. When I first got him he was pretty young and only a couple inches long. He was pretty calm for a while, but as he got older he began to become territorial. I had to buy a hollow log decoration for him to hide under because he became a wuss too! He nipped the fins of my black skirt tetras, long-finned serpae tetras, and cories. I ended up just getting danios to live with him because they are very quick and can out swim him. I really like him even though he is territorial, and he has always been healthy. He is up to about five inches long now, and I just put him in a bigger tank, so I hope he gets a little bigger. It is very entertaining to watch him because of his distinct personality!

From: Sharmine - Namibia
I have 4 Rainbows, 4 Silver Sharks and a Bala Shark for almost 3 years now. This little community seems to work perfectly. My sharks are playful, they hide, but love to come out and play. I named the one Pebbles, as he loves the marbles in my tank (pushing them around all over). My tank is well planted and with many hiding places. I think the Rainbows might just be a little misunderstood. Mine are generally calm and peacefull. I have however found that they do not like fish smaller than what they are. Hope this can help. I am not an expert on fish, but I love them. Currently I have 4 tanks, all different species divided into communities.

From: Josh
I have had an albino rainbow shark for years now. He's gotten long and real thick! He's at least 7 inches long, and almost an inch wide! Its hard to believe! When I first got him he was almost eaten by my oscar (had him in mouth) but I saved him and now he owns his current setup with 17 tiger barbs, 1 bala shark, 1 parrot fish, one pink convict cichlid, 1 florida flag fish, one paradise fish, and some algae eaters. They all get along great and there is never any fighting. I think mine might be a record in size!

Albino Rainbow Shark

From: Karen Olthoff
6 months ago I got one of these sharks for my new tank. It just keeps getting bigger and bigger! I put him in a bigger tank where he stressed out and got ick. I put him back in his original tank and all he does is hide in the plants all day. He is very shy and shares his tank with one tiny, also shy plecostomus.

From: Newbfishfreak
My experience with rainbow sharks is in line with what I've read here. My first tank included 2 rainbows, with an assortment of other good community fish. When I set it up I knew basically nothing and relied on the advice of the salesman. The sharks were so pretty I wanted 2 of them. Both were females. One was a good bit larger than the other. Sure enough, within a few days the larger started harassing the smaller - just constantly seeking her out and chasing her. Not really biting or tearing, just chasing. The big one pretty much ignored the other fish in the tank. It has continued for a few months and although the smaller has survived and still looks healthy, she just constantly hides behind plants, heaters or situates herself vertically in various corners of the tank. I feel so sorry for her. She doesn't seem to be enjoying life. The other one is so cocky and just swims around like she owns the tank.

I sure wish the salesman had told me the advice I have read here that you shouldn't get 2 of these together. To this point, the big one hasn't really bothered the other fish (including some small guppies) but that may come as she gets larger. I check the tank every morning dreading seeing the smaller one having just given up the ghost out of fatigue or stress. Should I get rid of one? I can't stand to just kill one. What is the procedure for returning a fish? Just take it back? I'd assume they would just dispose of it since it's not an expensive fish. The bad part is that I like both of them - the small one is beautiful and the big one has a great presence (aside from her bullying). Any advice?

Yep, take one of them back to the store and let them know of your experience and about what you have read about this fish's behavior. Maybe the sales clerk didn't know you shouldn't keep multiples in the same tank. If you told them, maybe it would prevent them from selling the next guy two of these rainbows. Definitely take it back and ask for a refund, or at least a store credit. They won't dispose of it. They will try to resell it. Do the right thing here.

From: Sammy Bo
Don't get two of these! I just bought 2 tonight from pet store, ticket showed they were passive, and I asked the sales woman if they were aggressive and she assured me they weren't. Got them home and put them in the tank and one has been harassing the other one all night. I'm taking the aggressive one back tomorrow, but keeping the other because it is very passive so far with other smaller fish and doesn't seem to mind them.

From: J
I wouldn't recommend them for a community aquarium. I never bought two, but I had one about a year and a half ago and whenever any fish smaller than him got near the middle, or bottom of my 20g tank he'd chase them as soon as he saw them. I brought this fish back, and the salesperson understood; most stores will take these back if you just explain why you bought them.

Though all fish have different personalities, the rainbow shark seems to be an all around aggressive species if kept with other fish. They are attractive fish, so if you must buy one, make sure you have a tank large enough for the other fish to swim around freely without aggravating it.

Excellent comment - thank you.

From: Sherra - two sharks in the same tank
I must have the pick of the litter when it comes to my rainbow sharks. I've seen a number of forums about these guys and many complain about them being aggressive, I just don't have that problem. So I must have the 2 biggest sissy rainbows. One I've had for 10 months and is about full size, while the other is new to the community about 4 to 5 months and half the size of the other one. I have them in a 20 gallon tank and they could care less about each other. The bigger one has his home in a log, while the other one swims around hanging out with the sword tails. When they come into contact with one another, there is no chasing or aggressive posturing. I'm no fish expert so I can't say why these 2 would get along, I just seem to have gotten lucky.
Thanks for your comments. You're right, this doesn't seem to be the norm when keeping multiples.

From: Matt and Tish
we have had our tank for about a year now, it consists of platys, zebra danos, corys and now our one rainbow shark. When first setting up our tank we bought one rainbow and one albino. At first they were fine with each other but as they got bigger the albino became very dominate with the other fish and would harass the other shark. The rainbow wouldn't eat and stayed very small. I found a home for the albino and now my rainbow shark is growing, seems happier and is a bit more active with the other fish.

From: Maheep
Hi, there is a very simple rule for rainbow n red fin sharks, and some other semi aggressive fish like blue Gourami, either keep single in an aquarium or keep atleast 4-5, that way the dominant one doesnt always chase the same fish of its species and all get enough time for rest beside company, i have 5 red fin and 1 rainbow, often they do their dominance dance around each other, if u know what i mean, but meanwhile a 3rd or 4th fish comes by and their focus shifts, day saved!! Its interesting to watch their moves and all, but ive never had any issues keeping 6of the same species, if its just a pair naturally the dominant one will always chase the same fish again n again all day long, killing its personality, the golden rule is, either keep 1 or many, 4-5 at least, never a pair!

More Rainbow Shark Tips

More Barb & Cyprinid Fish Profiles

Red Tail Shark
Epalzeorhynchus bicolor
Red Tail Shark
Another "freshwater shark" that is very territorial and will not do well with other red tails.
Rosy Barb
Barbus conchonius
Rosy Barb
Also known as the Red Barb, this fish should bring lots of activity to a tank.
Rosy Red Minnow
Pimephales promelas
Rosy Red Minnow
If being used as a feeder, they'll need to be quarantined, and medicated so that it will not pass on disease to your larger fish. It is best to breed your own rosy reds if you plan on using them as feeders.

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