Can Australian Smelt and Chao Phraya Giant Catfish (Paroon Shark) Live Together?

Australian Smelt is a peaceful species (1/10), while Chao Phraya Giant Catfish (Paroon Shark) is semi-aggressive (8/10). This notable difference means Chao Phraya Giant Catfish (Paroon Shark) may occasionally assert dominance over Australian Smelt.

Large aggression gap (7 points) between Australian Smelt and Chao Phraya Giant Catfish (Paroon Shark) increases stress risk for the more peaceful fish.

Australian Smelt and Chao Phraya Giant Catfish (Paroon Shark) both frequent the Middle (Open Water) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion. Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: Australian Smelt is a known jumper, so a tight-fitting lid is essential.

To improve the chances of a peaceful coexistence in this community tank: A larger aquarium with ample hiding spots can help diffuse aggression and give the less dominant fish space to retreat.

The safe temperature window for both species falls between 24°C and 24°C. Aim for the midpoint of this range (around 24.0°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 7.5. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–15 dGH. Regular testing will ensure conditions stay within this range.

To house Australian Smelt and Chao Phraya Giant Catfish (Paroon Shark) together, plan for an aquarium of at least 15000 litres with a minimum length of 600 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Because this pairing requires extra vigilance, include plenty of hiding spots — caves, driftwood, and dense plant clusters — so the less dominant fish can retreat when needed.

Specific environmental needs for this combination include: Plants - lighly covered, Smooth Gravel (Sensitive Barbels). Meeting these requirements will help both species thrive.

Both species do well with moderate (standard) water movement, so a standard filtration setup rated for the tank volume should suffice.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Australian Smelt and Chao Phraya Giant Catfish (Paroon Shark) need extra room, more cover, and closer observation during the first few weeks so small aggression, feeding, or territory issues do not snowball into a long-term problem.

Feeding time deserves special attention with this pairing. Chao Phraya Giant Catfish (Paroon Shark) is an aggressive eater that may prevent Australian Smelt from getting enough food.

Because Chao Phraya Giant Catfish (Paroon Shark) is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Australian Smelt receives an adequate share.