Can Colombian Shark Catfish (Brackish) and Golden Wonder Killifish Live Together?

Colombian Shark Catfish (Brackish) is a moderately assertive species (5/10), while Golden Wonder Killifish is moderately assertive (6/10). This modest difference means Golden Wonder Killifish may occasionally assert dominance over Colombian Shark Catfish (Brackish).

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

Worth noting: Golden Wonder Killifish is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 22°C and 28°C. Aim for the midpoint of this range (around 25.0°C) for optimal comfort.

Both fish can tolerate a pH between 7.5 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 12–20 dGH. Regular testing will ensure conditions stay within this range.

To house Colombian Shark Catfish (Brackish) and Golden Wonder Killifish together, plan for an aquarium of at least 380 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: Sand (Sifters), Plants - Floating. Meeting these requirements will help both species thrive.

Colombian Shark Catfish (Brackish) prefers High (River/Stream) flow while Golden Wonder Killifish needs Low (Still Water) flow. Consider positioning filter outlets and using baffles to create zones of different current intensity within the same tank.

This pairing usually fails when the tank is treated like a standard mixed community and the caution flags are ignored. Colombian Shark Catfish (Brackish) and Golden Wonder Killifish 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.