Can Electric Blue Johannii and Starlight Bristlenose Pleco (L183) Live Together?

Reviewed by Guidarium Editorial DeskUpdated May 11, 2026
Not Recommended

Electric Blue Johannii and Starlight Bristlenose Pleco (L183) 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

Electric Blue Johannii

Pseudotropheus johannii

Starlight Bristlenose Pleco (L183)

Ancistrus dolichopterus

🐠Family Group
Electric Blue Johannii
Cichlids - African
Starlight Bristlenose Pleco (L183)
Catfish
Temperament
Electric Blue Johannii
Aggressive (8/10)
Starlight Bristlenose Pleco (L183)
Mostly Peaceful (3/10)
Temperature
✓ Compatible
Electric Blue Johannii
24–28°C
Starlight Bristlenose Pleco (L183)
26–30°C
pH Range
✗ No overlap
Electric Blue Johannii
7.8–8.6
Starlight Bristlenose Pleco (L183)
5–7
Hardness (dGH)
✓ Compatible
Electric Blue Johannii
10–25
Starlight Bristlenose Pleco (L183)
1–10
Water Type
✓ Compatible
Electric Blue Johannii
Freshwater Only
Starlight Bristlenose Pleco (L183)
Freshwater Only
Flow Preference
✓ Compatible
Electric Blue Johannii
Moderate
Starlight Bristlenose Pleco (L183)
Moderate
Min Tank Volume
Combined: 204 L
Electric Blue Johannii
150 L
Starlight Bristlenose Pleco (L183)
75 L
Swimming Level
Shared: 1 zone
Electric Blue Johannii
MiddleBottom
Starlight Bristlenose Pleco (L183)
Bottom
🏷️Behavior Tags
Electric Blue Johannii
Generally AggressiveAggressive to same species/look-alikesTerritorial (Defends specific area)Digger (Disturbs Substrate)Plant DestroyerHyperactive / Fast Swimmer
Starlight Bristlenose Pleco (L183)
NocturnalShy / Slow Moving (Easily Stressed)
Stocking calculator

Can your tank handle Electric Blue Johannii and Starlight Bristlenose Pleco (L183)?

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.

Electric Blue Johannii
Starlight Bristlenose Pleco (L183)
Test both in my tank

Behaviour & Temperament

Electric Blue Johannii is a semi-aggressive species (8/10), while Starlight Bristlenose Pleco (L183) is generally mild-mannered (3/10). This notable difference means Electric Blue Johannii may occasionally assert dominance over Starlight Bristlenose Pleco (L183).

Electric Blue Johannii and Starlight Bristlenose Pleco (L183) 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.

Additional behavioural considerations to keep in mind: Aggressive fish may bully and stress shy, slow-moving species. 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.

Water Parameters

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.

The pH requirements of Electric Blue Johannii (7.8–8.6) and Starlight Bristlenose Pleco (L183) (5–7) do not overlap, making it impossible to satisfy both species simultaneously.

For general hardness, the shared comfort zone is 10–10 dGH. Regular testing will ensure conditions stay within this range.

Tank Setup

To house Electric Blue Johannii and Starlight Bristlenose Pleco (L183) together, plan for an aquarium of at least 204 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: Sand (Sifters), Established Algae (Otocinclus), Driftwood (Digestion/Hiding), Leaf Litter/Blackwater. 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

Electric Blue Johannii and Starlight Bristlenose Pleco (L183) 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 Electric Blue Johannii and Starlight Bristlenose Pleco (L183).

Show 5 more tank sizes

Frequently Asked Questions

Can Electric Blue Johannii and Starlight Bristlenose Pleco (L183) live together?

No. This combination is not recommended. Key incompatibilities — such as critical behavioural conflicts — make cohabitation unsafe.

What size tank do Electric Blue Johannii and Starlight Bristlenose Pleco (L183) need?

A minimum of 204 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 Electric Blue Johannii and Starlight Bristlenose Pleco (L183) together?

Keep the aquarium between 26°C and 28°C. A target of around 27.0°C sits comfortably within both species' preferred ranges.

Are Electric Blue Johannii or Starlight Bristlenose Pleco (L183) aggressive?

Electric Blue Johannii is semi-aggressive (8/10) and Starlight Bristlenose Pleco (L183) is generally mild-mannered (3/10). The gap in aggression levels means the calmer fish may experience stress from the more assertive one.

What pH do Electric Blue Johannii and Starlight Bristlenose Pleco (L183) need?

Their pH requirements do not overlap. Electric Blue Johannii prefers 7.8–8.6, while Starlight Bristlenose Pleco (L183) needs 5–7. 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 Starlight Bristlenose Pleco (L183) being nocturnal affect compatibility?

Starlight Bristlenose Pleco (L183) 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 Starlight Bristlenose Pleco (L183) during evening hours.

Editorial Review

Guidarium Editorial Desk

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

Last reviewed
May 11, 2026
Last updated
May 11, 2026
Issues or corrections?
Contact the editorial team

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