While the rainbow shark (Eplazeorhynchos frenatum) has a milder temperament than some other freshwater fished with "shark" in their names, the rainbow may still have trouble getting along with bottom-dwelling fish. However, the rainbow shark tends to get along with loaches, bottom-dwellers from its native range. However, individual rainbow sharks do vary in their temperament and age. Some individuals may consider any interloper in their territory at the bottom of the tank fair game.
My Sharks Fish Tanks Freshwater JAWS iridescent shark - YouTube
It is important to know when you choose to keep a freshwater shark fish they can be a threat to other fish companions, especially if there are small fish in the tank.
Tropical Fish for Freshwater Aquariums: Redtail Shark - Live Aquaria
Well, the truth of the matter is that these fish were sharks in name only. The fish I encountered that day was one of several species known in the freshwater aquarium industry as sharks. Actually closer kin to the carps than any true seagoing predator, the freshwater sharks can make aesthetically attractive, long-lived, and highly active additions to the freshwater aquarium, but great care should be taken when approaching any of these species for the first time, as they may be wary, flighty, or downright hostile to their tankmates should any or all of their captive requirements go unmet. If maintained in a habitat that offers a balance of food, territory, and hiding spaces, however, most of the freshwater sharks can be maintained by even the most moderately skilled hobbyists.
big freshwater aquarium shark fish - YouTube
Whether true freshwater sharks exist or not is still somewhat of an open question. There is no doubt that there are sharks that live in freshwater, but most of these species are really marine sharks that are able to migrate up into freshwater and live out their entire lives there. An example of such a shark is the bull shark which is notorious for wandering into freshwater and has been found over 4200 kilometers / 2,600 miles upstream in rivers such as the Amazon. Bull sharks also live in Lake Nicaragua and these sharks are often referred to as true freshwater sharks. Recent studies do however show that even if bull sharks can live for many years in Lake Nicaragua, they do not breed there and they need to return to the ocean to breed. The fact that the bull shark can live for prolonged periods in freshwater doesn’t really make it a freshwater fish as long as it can’t reproduce in freshwater. (Having to migrate from freshwater to saltwater or vice verse to breed is however not unheard of among fishes; the famous salmons runs do for instance occur when salmons migrate from the ocean to freshwater streams to spawn.) Health:
Iridescent sharks are one of the few pet freshwater fish which can live over 10 years. The average life span of an iridescent shark is 10-15 years, but some healthy individuals have been known to live till they are 20-25 years old. Strangely, the iridescent shark seems to have a problem with rubbing its nose against the aquarium glass. While this rarely hurts the fish, it makes their nose become a whitish-grey color since their rubbing the skin off.