Can Bristlenose Pleco and Electric Blue Johannii Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 4, 2026
Not Recommended

Bristlenose 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

Bristlenose Pleco

Ancistrus cf. cirrhosus

Electric Blue Johannii

Pseudotropheus johannii

🐠Family Group
Bristlenose Pleco
Catfish
Electric Blue Johannii
Cichlids - African
Temperament
Bristlenose Pleco
Peaceful (2/10)
Electric Blue Johannii
Aggressive (8/10)
Temperature
✓ Compatible
Bristlenose Pleco
22–27°C
Electric Blue Johannii
24–28°C
pH Range
✗ No overlap
Bristlenose Pleco
6–7.5
Electric Blue Johannii
7.8–8.6
Hardness (dGH)
✓ Compatible
Bristlenose Pleco
4–15
Electric Blue Johannii
10–25
Water Type
✓ Compatible
Bristlenose Pleco
Freshwater Only
Electric Blue Johannii
Freshwater Only
Flow Preference
✓ Compatible
Bristlenose Pleco
Moderate
Electric Blue Johannii
Moderate
Min Tank Volume
Combined: 229 L
Bristlenose Pleco
75 L
Electric Blue Johannii
150 L
Swimming Level
Shared: 1 zone
Bristlenose Pleco
Bottom
Electric Blue Johannii
MiddleBottom
🏷️Behavior Tags
Bristlenose Pleco
Nocturnal
Electric Blue Johannii
Generally AggressiveAggressive to same species/look-alikesTerritorial (Defends specific area)Digger (Disturbs Substrate)Plant DestroyerHyperactive / Fast Swimmer
Stocking calculator

Can your tank handle Bristlenose 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.

Bristlenose Pleco
Electric Blue Johannii
Test both in my tank

Behaviour & Temperament

Bristlenose Pleco is a peaceful species (2/10), while Electric Blue Johannii is semi-aggressive (8/10). This notable difference means Electric Blue Johannii may occasionally assert dominance over Bristlenose Pleco.

Large aggression gap (6 points) between Bristlenose Pleco and Electric Blue Johannii increases stress risk for the more peaceful fish.

Bristlenose 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: Bristlenose 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 27°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

The pH requirements of Bristlenose 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.

Tank Setup

To house Bristlenose Pleco and Electric Blue Johannii together, plan for an aquarium of at least 229 litres with a minimum length of 90 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.

Why This Pairing Usually Fails in Practice

Bristlenose Pleco and Electric Blue Johannii 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.

Suitable Tank Sizes

Standard aquarium sizes large enough for both Bristlenose Pleco and Electric Blue Johannii.

Show 3 more tank sizes

Frequently Asked Questions

Can Bristlenose 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 Bristlenose Pleco and Electric Blue Johannii need?

A minimum of 229 litres (tank length at least 90 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 Bristlenose Pleco and Electric Blue Johannii together?

Keep the aquarium between 24°C and 27°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Bristlenose Pleco or Electric Blue Johannii aggressive?

Bristlenose Pleco is peaceful (2/10) 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 Bristlenose Pleco and Electric Blue Johannii need?

Their pH requirements do not overlap. Bristlenose 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 Bristlenose Pleco being nocturnal affect compatibility?

Bristlenose 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 Bristlenose Pleco during evening hours.

Editorial Review

Guidarium Editorial Desk

Reviewed against Guidarium care, stocking, and compatibility standards. Read the editorial policy.

Last reviewed
May 4, 2026
Last updated
May 4, 2026
Issues or corrections?
Contact the editorial team

Related Comparisons