Can Australian Smelt and Green Phantom Pleco (L200) Live Together?

Australian Smelt is a peaceful species (1/10), while Green Phantom Pleco (L200) is moderately assertive (5/10). This notable difference means Green Phantom Pleco (L200) may occasionally assert dominance over Australian Smelt.

In terms of spatial distribution, Australian Smelt prefers the Top (Surface) and Middle (Open Water) zones, whereas Green Phantom Pleco (L200) 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: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Green Phantom Pleco (L200) 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.

There is no temperature overlap between Australian Smelt (15–24°C) and Green Phantom Pleco (L200) (25–30°C). This fundamental mismatch makes long-term cohabitation impractical.

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 5–12 dGH. Regular testing will ensure conditions stay within this range.

To house Australian Smelt and Green Phantom Pleco (L200) together, plan for an aquarium of at least 250 litres with a minimum length of 120 cm. This recommendation combines the stricter species minimums with a community-load allowance so the pairing has realistic long-term space and filtration headroom.

Providing a mix of open swimming space and sheltered areas with rocks, driftwood, or plants will keep both species comfortable and allow natural behaviour.

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

Note a potential conflict in setup requirements: Green Phantom Pleco (L200) 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.

Australian Smelt and Green Phantom Pleco (L200) are the kind of pair that can look acceptable in a shop but become a maintenance problem at home. The main risk is not a single number in the chart; it is the way incompatible behavior, water needs, or pressure on space compounds over time once both fish are established in the same tank.