Can Amazon Puffer and Threadfin Rainbowfish Live Together?

Amazon Puffer is a generally mild-mannered species (3/10), while Threadfin Rainbowfish is peaceful (1/10). This modest difference means Amazon Puffer may occasionally assert dominance over Threadfin Rainbowfish.

Amazon Puffer and Threadfin Rainbowfish both frequent the Middle (Open Water) and Top (Surface) 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. Shrimp eaters may also prey on very small nano fish.

Worth noting: Amazon Puffer is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Amazon Puffer 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. Keep fin nippers in larger groups to distribute nipping behaviour among conspecifics rather than tank mates.

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 5.5 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 4–12 dGH. Regular testing will ensure conditions stay within this range.

To house Amazon Puffer and Threadfin Rainbowfish together, plan for an aquarium of at least 96 litres with a minimum length of 75 cm. This accounts for the larger species' space requirements with an additional 20 % buffer to reduce territorial tension.

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), Driftwood (Digestion/Hiding), Plants - Densely covered, Shells (Breeding/Hiding), Plants - Floating. 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.

Feeding time deserves special attention with this pairing. Amazon Puffer is a known shrimp eater and may prey on small invertebrates or nano fish like Threadfin Rainbowfish.

Because Threadfin Rainbowfish is a fast, competitive feeder, consider using sinking pellets or feeding at opposite ends of the setup to ensure Amazon Puffer receives an adequate share.