Can Alligator Pleco and Electric Blue Johannii Live Together?
Alligator Pleco and Electric Blue Johannii are not recommended as tank mates due to conflicting pH requirements. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.
At a Glance
Can your tank handle Alligator Pleco and Electric Blue Johannii?
Compatibility is only part of the answer. Test both fish with your real tank size, current stock, and maintenance needs to see if you have enough space and a safe stocking level before you add them.
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Behaviour & Temperament
Alligator Pleco is a generally mild-mannered species (3/10), while Electric Blue Johannii is semi-aggressive (8/10). This notable difference means Electric Blue Johannii may occasionally assert dominance over Alligator Pleco.
Alligator Pleco and Electric Blue Johannii 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.
Worth noting: Alligator Pleco is nocturnal and will be most active after lights-out, naturally reducing daytime encounters.
Water Parameters
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.
The pH requirements of Alligator Pleco (6–7.5) and Electric Blue Johannii (7.8–8.6) do not overlap, making it impossible to satisfy both species simultaneously.
For general hardness, the shared comfort zone is 10–15 dGH. Regular testing will ensure conditions stay within this range.
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Tank Setup
To house Alligator Pleco and Electric Blue Johannii together, plan for an aquarium of at least 280 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: Driftwood (Digestion/Hiding), Established Algae (Otocinclus), Sand (Sifters). 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.
Suitable Tank Sizes
Standard aquarium sizes large enough for both Alligator Pleco and Electric Blue Johannii.
75 Gallon Standard
90 Gallon Standard
125 Gallon Standard
150 Gallon High
180 Gallon Standard
350 Liter (120cm Deep)
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Frequently Asked Questions
Can Alligator Pleco and Electric Blue Johannii live together?
No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.
What size tank do Alligator Pleco and Electric Blue Johannii need?
A minimum of 280 litres (tank length at least 120 cm) is recommended. This provides enough space for both species to establish their own areas and reduces the likelihood of territorial disputes.
What water temperature is best for Alligator Pleco and Electric Blue Johannii together?
Keep the aquarium between 24°C and 28°C. A target of around 26.0°C sits comfortably within both species' preferred ranges.
Are Alligator Pleco or Electric Blue Johannii aggressive?
Alligator Pleco is generally mild-mannered (3/10) and Electric Blue Johannii is semi-aggressive (8/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.
What pH do Alligator Pleco and Electric Blue Johannii need?
Their pH requirements do not overlap. Alligator Pleco prefers 6–7.5, while Electric Blue Johannii needs 7.8–8.6. This makes them incompatible in the same water chemistry.
How do I manage Electric Blue Johannii's territorial behaviour?
Provide line-of-sight breaks using rocks, driftwood, and dense planting. A larger tank gives Electric Blue Johannii space to claim a territory without encroaching on the other fish's area. Adding décor that divides the tank into distinct zones works especially well.
Does Alligator Pleco being nocturnal affect compatibility?
Alligator Pleco is most active after lights-out, which naturally reduces daytime encounters with its tank mate. This can actually be beneficial, as both fish get undisturbed time to feed and explore. Just ensure food reaches Alligator Pleco during evening hours.
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