Can Alligator Pleco and Blue Back Blue Eye Live Together?

Not Recommended

Alligator Pleco and Blue Back Blue Eye are not recommended as tank mates due to incompatible water types. Housing these species together is likely to result in stress, health problems, or direct harm to one or both fish.


At a Glance

Alligator Pleco

Pterygoplichthys scrophus

Blue Back Blue Eye

Pseudomugil cyanodorsalis

🐠Family Group
Alligator Pleco
Catfish
Blue Back Blue Eye
Rainbowfish
Temperament
Alligator Pleco
Mostly Peaceful (3/10)
Blue Back Blue Eye
Peaceful (2/10)
Temperature
✓ Compatible
Alligator Pleco
23–28°C
Blue Back Blue Eye
22–30°C
pH Range
✓ Compatible
Alligator Pleco
6–7.5
Blue Back Blue Eye
7–8.5
Hardness (dGH)
✓ Compatible
Alligator Pleco
4–15
Blue Back Blue Eye
10–30
Water Type
✗ No overlap
Alligator Pleco
Freshwater Only
Blue Back Blue Eye
Brackish Required
Flow Preference
✓ Compatible
Alligator Pleco
Moderate
Blue Back Blue Eye
Moderate
Min Tank Volume
Combined: 280 L
Alligator Pleco
280 L
Blue Back Blue Eye
38 L
Swimming Level
✓ Different zones
Alligator Pleco
Bottom
Blue Back Blue Eye
TopMiddle
🏷️Behavior Tags
Alligator Pleco
NocturnalPlant DestroyerDigger (Disturbs Substrate)Aggressive to same species/look-alikes
Blue Back Blue Eye
Nano / Bite-sized (Predation Risk)Jumper (Lid Required)Hyperactive / Fast SwimmerFry Predator
Stocking calculator

Can your tank handle Alligator Pleco and Blue Back Blue Eye?

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.

Alligator Pleco
Blue Back Blue Eye
Test both in my tank

Behaviour & Temperament

Alligator Pleco is a generally mild-mannered species (3/10), while Blue Back Blue Eye is peaceful (2/10). This modest difference means Alligator Pleco may occasionally assert dominance over Blue Back Blue Eye.

In terms of spatial distribution, Alligator Pleco prefers the Bottom (Substrate) zone, whereas Blue Back Blue Eye 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.

Worth noting: Alligator Pleco is nocturnal and will be most active after lights-out, naturally reducing daytime encounters. Also, Blue Back Blue Eye is a known jumper, so a tight-fitting lid is essential.

Water Parameters

The safe temperature window for both species falls between 23°C and 28°C. Aim for the midpoint of this range (around 25.5°C) for optimal comfort.

Both fish can tolerate a pH between 7 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 10–15 dGH. Regular testing will ensure conditions stay within this range.

Crucially, these species require different water types — one needs freshwater while the other requires brackish conditions. This is a hard barrier to keeping them together.

Tank Setup

To house Alligator Pleco and Blue Back Blue Eye 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 Blue Back Blue Eye.

Show 1 more tank size

Frequently Asked Questions

Can Alligator Pleco and Blue Back Blue Eye live together?

No. This combination is not recommended. Key incompatibilities — such as different water type needs — make cohabitation unsafe.

What size tank do Alligator Pleco and Blue Back Blue Eye 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 Blue Back Blue Eye together?

Keep the aquarium between 23°C and 28°C. A target of around 25.5°C sits comfortably within both species' preferred ranges.

Are Alligator Pleco or Blue Back Blue Eye aggressive?

Alligator Pleco is generally mild-mannered (3/10) and Blue Back Blue Eye is peaceful (2/10). Their similar temperaments generally lead to a peaceful coexistence.

What pH do Alligator Pleco and Blue Back Blue Eye need?

Both species overlap in the 7–7.5 pH range. Consistency is key — avoid sudden swings, and test regularly to stay within this window.

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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