Iridescent Shark Care Guide: Simple Tips for Happy Fish

Iridescent sharks, also known as Siamese sharks and iridescent catfish, are fascinating creatures that can captivate both novice and experienced aquarists. Although they’re not true sharks, their appearance and size make them an intriguing addition to large home aquariums. Scientifically named Pangasianodon hypophthalmus, these freshwater inhabitants are a part of the Pangasiidae family, sharing it with the Mekong Giant Catfish, one of the largest freshwater fish in the world.

If you’re considering adding an iridescent shark to your aquatic collection, it’s essential to understand their care requirements, diet, and breeding habits. This care guide will provide you with the knowledge necessary to maintain a happy, healthy environment for your iridescent shark.

As a responsible aquarium enthusiast, it’s crucial to know that these fish can grow quite large, reaching lengths of over 4 feet in some cases. So make sure to have ample space and resources to accommodate their needs before you welcome this stunning creature into your aquatic family.

Species Overview

Iridescent sharks are captivating freshwater fish known for their shimmering appearance. They belong to the Pangasiidae family, with the scientific name Pangasianodon hypophthalmus. While they share some resemblance with saltwater sharks, these gentle creatures have distinct characteristics and care requirements.

In their natural habitat, iridescent sharks are mainly found in Southeast Asia’s Mekong and Chao Phraya rivers. As they can grow quite large, it’s essential for aquarists to provide ample space and proper living conditions, making them suitable only for well-prepared enthusiasts.

Below is a table summarizing crucial aspects of iridescent shark care:

Property Information
Scientific name Pangasianodon hypophthalmus
Common names Iridescent shark, Siamese shark, Sutchi catfish
Distribution Southeast Asia, Mekong and Chao Phraya rivers
Size Up to 4 feet (though usually smaller in captivity)
Lifespan Up to 15 years
Diet Omnivorous
Temperament Peaceful
Minimum tank size 500 gallons
Temperature 72-79°F (22-26°C)
pH 6.5-7.5
Water hardness 2-20 dGH
Care level Intermediate
Filtration/Water Flow Moderate to high
Water type Freshwater
Breeding Egg-layers, challenging in captivity
Breeding difficulty Difficult
Compatibility Best with similarly-sized, non-aggressive species

Iridescent Shark Basics

Iridescent sharks are fascinating freshwater fish that can truly captivate the attention of any aquarist. In this section, we will explore their origins, natural habitat, physical characteristics, and lifespan. As you read, you’ll gather valuable information to help you provide the best possible care for these unique creatures.

Origins and Natural Habitat

Iridescent sharks, also known as iridescent catfish, are native to Southeast Asia. They can be found in rivers, basins, and large bodies of water such as the Mekong River. These fish prefer living in a freshwater environment with a consistent flow and are generally found in deeper sections of the river.

Size and Shape

When it comes to size and shape, iridescent sharks are known for their impressive growth rate. They start at around 2.5 to 4 inches in length when purchased and can reach a foot in length within a year. In the wild, these fish can grow to be more than 4 feet long, but they usually stay smaller in captivity. They have a streamlined body shape with a slightly downturned mouth, resembling a miniature shark.

Color and Markings

Iridescent sharks are named for their unique coloration. They have a silver or gray body that exhibits an iridescent sheen, which is more pronounced in juveniles. As they mature, the glow becomes more subtle, but the fish still retains an eye-catching appearance. These fish have dark stripes that run along the sides of their bodies, adding an interesting contrast to their overall coloration.


Provided with proper care and optimal living conditions, an iridescent shark can live for 20 years or more. In order to ensure a long and healthy life, it’s crucial that you maintain high water quality, a balanced diet, and appropriate tank mates for your iridescent shark. By keeping their environment as close to their natural habitat as possible, you will help these captivating fish thrive.

Care and Tank Requirements

Caring for your iridescent shark requires attention to various aspects, including tank size, water parameters, tank setup, and decorations. In this section, we will discuss these requirements to ensure you provide the best environment possible for your iridescent shark.

Tank Size

As the iridescent shark grows, your tank size must accommodate their needs. For a single adult iridescent shark, a 300-gallon tank is the minimum requirement. If you plan to keep more than one, you’ll need an additional 150-gallons per shark. Keep in mind that iridescent sharks prefer to school, so a larger aquarium or aquatic space of at least 40 feet in length is recommended.

Water Parameters

Maintaining proper water parameters is essential for the well-being of your iridescent shark. Ensure the water temperature stays consistent, and aim for the following values:

  • Water temperature: between 72-79°F.
  • pH level: 6.5-7.5.
  • Water hardness: 2-20 dGH.
  • Water flow rate: moderate.

To maintain clean water, invest in a strong filter and change around 25% of the water weekly.

Tank Setup

When setting up your iridescent shark’s tank, consider the following factors:

  • Substrate: Choose a soft substrate, such as sand or small, smooth gravel to prevent injury.
  • Plants: Incorporate plants like Java Fern, Anubias, and Vallisneria, but ensure they won’t be easily uprooted by your active iridescent shark.
  • Lighting: Moderate lighting is recommended, as dim light will make your iridescent shark feel more comfortable and less stressed.

Place the tank in a quiet, low-traffic area to help your iridescent shark remain calm and prevent injuries from sudden movements.


Include decorations in your iridescent shark’s tank to enrich their environment and provide them with hiding spots. Consider driftwood, rock formations, and caves. However, make sure to avoid sharp edges and materials that could harm your iridescent shark during their active swimming sessions. Focus on creating a natural-looking environment with plenty of open space for swimming, as this is essential to their wellbeing.

Diet and Feeding

Nutritional Needs

Your Iridescent Shark has diverse nutritional needs as they eat a variety of food in the wild. To maintain their health and the beautiful iridescent hue, you should provide a balanced diet consisting of:

  • High-quality pellets or flakes: Choose pellets or flakes specially formulated for large omnivorous fish.
  • Meaty foods: Occasionally offer frozen or live foods such as shrimp, insects, and small fish to mimic their natural diet.
  • Vegetation: Supplement their diet with vegetables like blanched spinach, cucumber, or zucchini.

Remember always to thaw frozen foods before feeding them to your Iridescent Shark, and avoid overfeeding them.

Feeding Schedule

To ensure proper growth and health, it’s essential to establish a regular feeding schedule for your Iridescent Shark. Here are a few tips:

  • Frequency: Feed your Iridescent Shark 2 to 3 times a day.
  • Portions: Offer enough food that they can consume within 2-3 minutes at each feeding.
  • Variety: Rotate between different types of food to encourage proper nutrition and prevent picky eating habits.

Following these dietary recommendations will keep your Iridescent Shark happy, healthy, and thriving in their aquarium environment. Remember to closely monitor their eating habits and adjust their feeding schedule as needed to prevent overfeeding or underfeeding.

Behavior and Temperament

Iridescent sharks (Pangasianodon hypophthalmus) are social and active creatures, so it’s important to create a suitable environment for them to thrive. In your aquarium, provide them with plenty of space to swim as they enjoy being on the move.

These fish are often timid in nature, especially when they’re young. It’s normal for them to hide in the initial stages, but they become bolder as they grow. To help them feel secure, give them hiding spots like caves and plants in your tank.

Remember to choose tank mates carefully as iridescent sharks prefer a peaceful environment. They get along well with other similarly sized, non-aggressive species. Avoid putting them with aggressive tank mates, as this may cause stress or even conflict.

Suitable Tankmates

Finding the right tankmates for your iridescent shark is essential to maintain a peaceful and stress-free environment in your aquarium. While these fish are generally gentle giants, they can sometimes act skittish or become stressed in incompatible conditions.

So, it’s crucial to find tankmates that are peaceful and compatible in terms of water parameters and behavior. While it’s always a good idea to keep iridescent sharks in small groups, pairing them with other suitable species creates a diverse and stimulating environment.

Here are some suitable tankmates for your iridescent shark:

  • Silver Dollars
  • Bala Sharks
  • Clown Loaches
  • Oscars
  • Discus
  • Angelfish
  • Elephant Nose Fish

Remember to keep an eye on your tank and monitor the interactions between your iridescent shark and its tankmates. If you notice any signs of stress or aggression, it’s important to address the issue promptly to maintain a harmonious living space for all of your aquatic pets. By choosing the right tankmates and providing a caring environment, your iridescent shark can thrive and continue to grow safely in your aquarium.

Breeding and Reproduction

Breeding iridescent sharks in captivity is highly challenging due to their specific breeding requirements and migratory behavior. Their need for vast amounts of space and migration before breeding cannot be replicated in a home aquarium.

Iridescent sharks are farm-raised in Southeast Asia using large outdoor ponds of thousands of gallons. These conditions allow for schooling and pairing off during spawning, sometimes with the use of hormones to stimulate breeding.

However, for most individuals, breeding iridescent sharks is unrealistic. Their size, migratory behavior, and vast space requirements make it nearly impossible for beginners or those without a massive pond and year-round tropical temperatures.

These fish rely on migrating upstream during the late summer months when water levels rise to breed in large ponds in Southeast Asia, providing the necessary space for spawning adults.

Replicating these natural breeding conditions within a home aquarium is extremely challenging and not feasible. Migration, in particular, is a crucial factor that cannot be accomplished in captivity.

The difficulty in breeding iridescent sharks emphasizes the importance of conservation efforts to protect their natural habitat, as pollution and human impacts pose threats to their population and breeding grounds.

Common Diseases and Treatments

Iridescent sharks are prone to a few common diseases, but with proper care and attention, you can keep your fish healthy. Here’s a brief overview of some common diseases and their respective treatments:

Ich: Also known as white spot disease, Ich is caused by a parasite that leads to small white spots on your fish’s body. To treat Ich in your iridescent shark, increase the water temperature to around 86°F (30°C) for a few days and use an appropriate medication specifically designed for treating Ich.

Fin Rot: This bacterial infection can cause frayed or disintegrating fins. To combat fin rot, maintain high water quality and use a medication specifically designed to treat bacterial infections.

Fungus: Fungal infections can appear as fuzzy patches on your fish’s body. To treat fungal infections, use a commercially available antifungal medication for aquarium fish and ensure that your water parameters are within an acceptable range.

Stress and Skinny Disease: Stress affects the immune system of your iridescent shark, which can lead to weight loss and other health problems. Maintain a stable, stress-free environment by providing a suitable tank size, hiding spots, and proper water conditions. Provide a varied diet to promote healthy growth.

To prevent these diseases and promote good health in your iridescent shark, always maintain the appropriate water parameters, tank size, and cleanliness. Perform regular water changes, test the water frequently, and provide a balanced diet to keep your fish healthy and happy.

Frequently Asked Questions

What do iridescent sharks eat?

Iridescent sharks are omnivorous and will eat a variety of foods. They enjoy a healthy balance of both plant-based and meat-based foods. You can feed them high-quality pellets, frozen or live brine shrimp, bloodworms, and vegetables such as lettuce or spinach. Make sure to give them a diverse diet to ensure their health and happiness.

Can iridescent sharks live with goldfish?

While it may initially seem like a good idea to house iridescent sharks with goldfish, it’s not the best choice for either species. Iridescent sharks grow quite large and require strong filtration and a lot of space, while goldfish produce a significant amount of waste and can quickly decrease water quality. It would be best to keep these two species in separate tanks with appropriate tank mates.

How long do iridescent sharks live?

With proper care, iridescent sharks can live up to 20 years. This means you need to be prepared for a long-term commitment to maintaining the proper tank conditions, diet, and environment for your iridescent shark throughout their lifetime.

What is the maximum size of a fully-grown iridescent shark?

A fully-grown iridescent shark can reach up to 4 feet in length. Given their size, it’s essential to provide them with a large tank. While a 60-gallon tank might be suitable for a juvenile, a fully-grown iridescent shark will require an aquarium or aquatic space that is at least 300 gallons or larger.

Are iridescent sharks real sharks?

Despite the name, iridescent sharks are not actual sharks; they are a type of catfish. Scientifically known as Pangasianodon hypophthalmus, they share a family with the Mekong Giant Catfish, one of the largest freshwater fish in the world.