Can Starlight Bristlenose Pleco (L183) and Swordtail Live Together?

Starlight Bristlenose Pleco (L183) is a generally mild-mannered species (3/10), while Swordtail is generally mild-mannered (4/10). This modest difference means Swordtail may occasionally assert dominance over Starlight Bristlenose Pleco (L183).

In terms of spatial distribution, Starlight Bristlenose Pleco (L183) prefers the Bottom (Substrate) zone, whereas Swordtail occupies the Top (Surface) and Middle (Open Water) zones. 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: Starlight Bristlenose Pleco (L183) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Swordtail is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 26°C and 28°C. Aim for the midpoint of this range (around 27.0°C) for optimal comfort.

Both fish can tolerate a pH between 7 and 7. Maintaining a stable value within this band is more important than hitting an exact number.

Hardness requirements are incompatible: Starlight Bristlenose Pleco (L183) needs 1–10 dGH while Swordtail requires 12–30 dGH.

To house Starlight Bristlenose Pleco (L183) and Swordtail together, plan for an aquarium of at least 110 litres with a minimum length of 80 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: Driftwood (Digestion/Hiding), Leaf Litter/Blackwater, Established Algae (Otocinclus), Plants - Densely covered. 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.

Starlight Bristlenose Pleco (L183) and Swordtail 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.