Can Flash Pleco (L204) and Silver Prochilodus Live Together?

Both Flash Pleco (L204) and Silver Prochilodus are generally mild-mannered species with an aggression score of 4/10. Their matching temperaments mean neither fish is likely to dominate the other in a shared aquarium.

Flash Pleco (L204) and Silver Prochilodus both frequent the Bottom (Substrate) region of the setup. This overlap can increase competition for space, so providing ample room and cover is important to keep both species comfortable.

There is a critical concern: the Shy / Slow Moving (Easily Stressed) behaviour of one fish directly conflicts with the Slime Coat Eater (Attacks Flat Fish) trait of the other — slime coat eaters target slow-moving fish, causing severe stress and health issues..

Additional behavioural considerations to keep in mind: Hyperactive swimmers can stress shy, slow-moving species through constant motion.

Worth noting: Flash Pleco (L204) is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Silver Prochilodus is a known jumper, so a tight-fitting lid is essential.

The safe temperature window for both species falls between 24°C and 28°C. Aim for the midpoint of this range (around 26.0°C) for optimal comfort.

Both fish can tolerate a pH between 6 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 2–15 dGH. Regular testing will ensure conditions stay within this range.

To house Flash Pleco (L204) and Silver Prochilodus together, plan for an aquarium of at least 450 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.

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), Smooth Gravel (Sensitive Barbels), Established Algae (Otocinclus). 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.

Flash Pleco (L204) and Silver Prochilodus 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.