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This page will give a completely detailed profile of the selected fish, from A to Z. The profiled fish will be chosen randomly by Badman, and will come from the complete genre of tropical fish. New profiles are added on a regular basis. If you would like to submit a profile for the site please contact me. Don't forget to let us know you experiences with this fish by filling out the



Epalzeorhynchus bicolor

Epalzeorhynchus bicolor
Formerly Labio Bicolor


    Not really a "shark" But with the shape of the dorsal fin the name became obvious. The striking color contrasts makes this one of the most sought after fish. Aggressive to one another they should not be kept in groups.

Quick stats:
    Listed tank sizes are the minimum
    Size: Up to 6" (15cm)
    Tank: 36 inches
    Strata: Bottom-middle
    PH: 6.0 to 7.5
    Hardness: Soft to medium. dH range: 5-18
    Temperature: 73°F to 84°F (23-29°C)


    Order: Cypriniformes
    Suborder: Cyprinoidei
    Family: Cyprinidae
    Genera: Epalzeorhynchus
Red tail Black shark


Common name

    Red tailed Black shark

Image gallery:
    Additional species photographs


    Badmans' Forum


    In the streams of Thailand.

General Body Form
    A large Dorsal fin, usually held upright with its outer back edge concave. Belly profile slightly curved and the back is very convex. Down-facing mouth, with two set of barbels. The body id slightly compressed and long. They can reach a length of about five inches, with the females larger than the males.

    A Reddish-Orange to Red Caudal fin with the Pectoral fins being the same or sometimes dark. If the fish is in good condition the rest of the body, including the rest of the fins is Velvet or jet Black. There are some color variations but the one described is the one most commonly seen. Specimens that are in poor health or not kept in the proper conditions will appear pale and washed out.
Epalzeorhynchus bicolor

    A fish that can be kept easily in the home aquarium for many years. Their water temperature should be kept between 75 and 80 degrees F. The water hardness should be on the soft side and not contain too many dissolved salts. They also benefit from frequent water changes. A larger aquarium is best to house these fish as if you are going to keep more than one as pecking order will be established, with one fish controlling the whole group. You will be able to identify the leader by its intense coloration. Hiding places must be provided. The tank should not be lit to bright as the fish are shy. Decorations should include driftwood and live plants, for more information go to the Biotope page on details on how to set up an Asian water tank. Diet should be balanced with a good flake food, occasional live food and supplemented with some vegetable matter. All in all Epalzeorhynchus Bicolor is a fine and colorful addition to any aquarium.


    Clear and muddy waterways littered with wood and stones

    Reports of hobbyist breeding Epalzeorhynchus Bicolor are very rare. What I have found is that a large well planted tank with a ratio of more females to males is needed. The females are more robust and rounded than the males. A spawning tube will appear weeks before spawning and the male fertilizes the eggs in jerky thrusting motions as the eggs are scattered. It is said that the eggs hatch in a couple of days and the fry are easy to raise. Most breeding is done in open ponds in their native Thailand and exported around the world.

Your comments:


Please remember that the following comments are personal experiences and may or may not apply to your setup. Use them as guide to help better understand your fish, like us all individuals will behave differently under different circumstances.


From: Nancy
I ADORE these fish, they have great personalities but they can be aggressive/territorial. Mine is the centerpiece of my 55 gal tank & I give a lot of thought to every fish I ad with him. I recently added Otocinclus Cats for algae control & became they're so cute and the Shark was chasing them for a few days but then settled down - I was ready to move him if need be but he was just asserting his dominance & once done he settled back down. I even saw him let one of the Oto's clean him with it's mouth, I thought he'd turn around & go after the Oto but then the Oto stopped & he actually asked for more & the Oto obliged. It was so neat to watch! If your RTBS gets too aggressive you can try moving it to another tank temporarily & changing the decor of the tank somewhat & add more caves, hiding places & then re-introduce the Shark and it will have to readjust, sometimes that will straighten them out & peace will reign again. If you do notice the Shark chasing certain fish or species as long as no ones fins are suffering then it's probably just play, but if the Shark is doing actual damage to another fish or harassing it so much it can't eat then it would be best to get that fish out of the tank. They are beautiful fish and make great pets but they do need a large tank, preferably 55 gal & up once they start to get some size to them. I plan to get my 3 yr old another RTBS as a tank mate but I know it may not work out so I have another tank for the new one if "Sharky" doesn't appreciate my effort to give him/her a playmate. They also like to interact/play with Cory Cats & Kuhli Loaches - at least the ones I've had always have & still do. The current one I have even shares his cave with the loaches.
From: David E.
I've kept these with fish for 20 years. They are all different, and their personalities can change with age. I believe the males are more aggressive, or maybe just more territorial. Difficult to say generally since they are so individual. Some are fine in mixed tanks, others will chase everything to the death. However their characters make them interesting. Just take care, and more them if they cause trouble.
From: David
I have heard from many sources that Red-tails should not be kept with related or similar fish. My shark gets along fine with my two Siamese Algae Eaters that he shares his Asian tank with. He even gets along with my dwarf gourami, my harlequin rasboras, and my zebra danios. He only gets feisty when anything gets in his cave. Then it is usually just a fin nip and a chase. However, not all red tails will have a peaceful personality like mine. For instance, I had a red tail about two years ago that killed all of his tankmates, which included 8 Neon Tetras, 4 Otocinclus, a Chinese algae Eater, 2 Angelfish, and 2 cory cats. Remember, every red tail has a different personality.
From: Kevin R. Stringer
I am a huge fan of this fish, having kept them since I began in the hobby as a preteen. They are usually quite passive and do not bother other fish in a community setting unless bullied first. Then, they are usually able to give as good as they get. The only exception to this is some Cichlids that are more aggressive and can bully them to the point of illness or death. Though this fish can adapt to just about any water conditions in terms of PH or hard/soft water, they really do best in soft, slightly acidic water. They are somewhat forgiving of water quality, but shouldn't have to be. Again, this is a wonderful fish. I have never tried to keep more than one in a tank at a time, but as a single species in various community tanks I've had over the years, they are a great addition!
From: Brian
I have a small one that I have recently added to my 29 gallon tank and he seems to be doing well. As far as I can tell likes to eat algae more than anything else at this point. He has been very peaceful so far, even ignoring the glolite tetras. The clown loach who is slightly larger than him does bully him a bit. He swims in the mid-strata occasionally but stays on the bottom mostly and sometimes hides in caves.
From: Ben
I love these fish, but in my one year experience with one of them I have found out(the hard way usually) that they are very aggressive towards almost any fish that is smaller than them, including barbs, tetras and even gouramis. My red-tailed shark simply won't tolerate any newcomers to his 30 gallon home!
From: Jake O'Farrell
These are beautiful fish in the correct conditions. Keep them in a 36 inch tank minimum, with live plants, caves,bogwood and driftwood. Be very cautious when housing them with small, slow fish, also be careful with small cave dwellers that may intrude on the sharks territory as they can be aggressive and injure/kill them.

From: Josh
My shark likes to lie vertical to the intake on the filter. Half the time I think he is dead. It must feel like a jacuzzi of somethin!

From: Kevin
My shark has started to become more aggressive toward my severum. Make sure your tank provides enough room for the shark to have an established territory (cave, rocks, etc.)

From: Michael
When I got my first red tailed black shark I put him in he was fine I walked off with the lid off I came back about 10 mins or more later and he was on the floor all dry up so I quickly put him in my tank and shaked him around he was starting to swim when he just went to the bottom I said hell make it so the next morning I woke up and he was playing around like noting happen today still he is my biggest and favourite fish in my comunity tank.

From: Andy
I never see mine unless I am cleaning the tank. He stays in the cave and doesn't come out, but that might be because he is scared of the oscar.






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