Can Australian Smelt and Yellow Bullhead Catfish Live Together?

Australian Smelt is a peaceful species (1/10), while Yellow Bullhead Catfish is moderately assertive (6/10). This notable difference means Yellow Bullhead Catfish may occasionally assert dominance over Australian Smelt.

In terms of spatial distribution, Australian Smelt prefers the Top (Surface) and Middle (Open Water) zones, whereas Yellow Bullhead Catfish occupies the Bottom (Substrate) zone. Because they use different levels of the water column, territorial disputes are less likely and the tank will appear more balanced.

Additional behavioural considerations to keep in mind: Aggressive eaters may outcompete shy fish for food, leading to malnutrition.

Worth noting: Yellow Bullhead Catfish is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, 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 15°C and 24°C. Aim for the midpoint of this range (around 19.5°C) for optimal comfort.

Both fish can tolerate a pH between 6.5 and 8. Maintaining a stable value within this band is more important than hitting an exact number.

For general hardness, the shared comfort zone is 5–20 dGH. Regular testing will ensure conditions stay within this range.

To house Australian Smelt and Yellow Bullhead Catfish together, plan for an aquarium of at least 500 litres with a minimum length of 150 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), Sand (Sifters), Driftwood (Digestion/Hiding). Meeting these requirements will help both species thrive.

Note a potential conflict in setup requirements: Yellow Bullhead Catfish is a plant destroyer, which conflicts with Australian Smelt's requirement for live plants. Compromise where possible or prioritise the more critical need.

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 Yellow Bullhead Catfish 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. Yellow Bullhead Catfish is an aggressive eater that may prevent Australian Smelt from getting enough food.

Because Yellow Bullhead Catfish 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.