Iridescent shark is one of the largest freshwater fishes. While buying, make sure you have a large tank to accommodate their 4 foot length as they mature. 

Why we need the beginner’s guide for this fish? This fish, though larger in size, very timid in nature. They get scared easily. Beginners guide will tell you how not to scare the fish and give it a peaceful ambiance for its healthy growth.

Iridescent Shark Fish – Overview

Common NameIridescent sharks are also commonly called Sutchi catfish or Siamese sharks.
Scientific NameThe scientific name of this fish is Pangasianodon hypophthalamus.
Habitat or OriginThey have their origin in Thailand and South East Asia. Their habitat is freshwater like ponds, deep rivers, etc.,
Average SizeThe adult fish is really large in size. The size of an adult fish can reach up to 4 feet.
ColorationTheir body is silver in color. The dorsal side is darker. The skin is shiny when they are juveniles. Above and below the lateral two black stripes are seen. As adults, they become grey.
Life SpanThis fish can live up to 20 years in proper condition. The fish should have a stress-free environment.
DietThe fish can diet on almost anything. They eat plants, live or frozen food, pellets, or wafers. They can be fed 2 -3 times a day so much as to finish their food in 5 minutes. They can be given live bloodworms or brine shrimp. They can also be given crickets or worms. Live fishes can also be given but make sure they do not bring disease to the Iridescent.
Gender IdentificationFemales are larger and plumper than males.
BehaviorThis fish likes to be in a school when they are juveniles but as they mature they separate. They are not only peaceful fishes but are also timid in nature. That is they can easily be scared. When they are scared, they hit their head on the tank. Hence it is important to keep them in a place where there is less noise and away from aggressive fishes. The fish is active during the day.
CompatibilityThis fish is a peaceful large fish. Hence aggressive fishes and small fishes should be avoided. Small fishes can sometimes become food for Iridescent fish due to their size. The fishes that can be kept with them are Pearsei, Oscar, Plecostomus, Synodontis catfish, Texas cichlid, Bichir, Fire Eel, Salvin’s cichlid, kissing gourami, Silver dollars. No crustaceans should be kept along with. Young Iridescents can be kept together in a group of 3 or 5.
Ideal Tank ConditionsAs juveniles, they require a minimum of 100 gallons of the tank. The mature ones can either be kept in a pond or they require a very large aquarium of 300 gallons at minimum. The tank should have rocks and driftwoods but the swimming space should be open. The middle water column should be left free as they are middle tank dwellers. The substrate should be soft as the fish has sensitive barbells. The lighting can be moderate. A powerful filtrate is required as this fish is messy.
Water ParametersThe temperature of the fish should be 72-79 degrees F. the pH can range from 6.5-7.5. The hardness can be 2-20 dH. Water movement can be moderate.
BreedingBreeding is impossible in captivity. In the wild, they move upstream while spawning. After spawning they go deep and lower into the water to take care of their eggs and young ones.
Common DiseasesThey are susceptible to Ich and fungal disease. Ich is seen as white spots on the body. Skin fungus is very common for this fish. Maintaining the water quality is a must to avoid disease. In case of disease, the fish can be treated with medication.
Approximate CostThe fish can cost $25 approximately. For this cost, the size should be 2 -3 inches.
What to look when buyingThe fish should appear healthy. If the fish is juvenile, it should have shiny skin. Avoid fishes that have a white spot on the body.
Species in the MarketRed tail sharks, Mekong Giant Catfish are other species found in the market.

Gallery of Iridescent Shark Fish


Pangasianodon hypophthalmus