Bristlenose pleco and Electric yellow cichlid
Can these two share a tank? The assessment below is derived from stored behavioural and environmental traits, not from a compatibility chart.
Workable only in unusual circumstances. Not a pairing to plan around.
- Minimum volume
- 375 L
- Minimum length
- 165 cm
- Factors considered
- 8
Concerns
pH ranges overlap only across 7.6–7.8, which is tighter than most tap-water supplies hold naturally.
Derived from: environment.ph overlap width
Electric yellow cichlid becomes markedly more aggressive while spawning. A pairing that has been peaceful for months can change within a day, so plan for where the other animal goes if it does.
Derived from: traits.breedingAggression
Bristlenose pleco defends a territory and both animals use the same part of the tank, so give the territory-holder a defensible area away from the main swimming space.
Derived from: traits.territoriality and zone on both records
Why it can work
- Temperature requirements overlap comfortably at 23–27 °C, with room for both animals to sit inside their preferred range.
- Hardness requirements overlap at 10–20 °dGH.
- Electric yellow cichlid needs a group of at least 4. Kept in smaller numbers it is not simply lonely — shoaling species held below their threshold show chronic stress behaviour, colour loss and, in several species, increased aggression towards tankmates.
- The two occupy different levels of the tank, which reduces direct competition for space.
- Bristlenose pleco is active mainly after dark, so the two overlap less than the stocking list suggests. Feed the nocturnal animal after lights-out or it will be outcompeted.
Conditions
Most interesting pairings are conditional on something. These are the things the keeper can actually change.
- At least 4 Electric yellow cichlid, counted as one group
- At least 375 L with a footprint of 165 cm or more, before counting anything else in the tank
Derived, or documented?
These are different claims and are shown separately. The verdict above is derived from stored traits — arithmetic on AquariumHQ's own records. Whether the pairing is actually reported to work is a separate question, and for most pairs the honest answer is that we hold nothing.
Environmental compatibility
Derived from stored traits
Temperature, pH, hardness, size and behavioural traits compared between the two records. Sound as far as it goes, and it is not evidence that the pairing works.
Behavioural evidence
Widely reported in practice
Reported consistently across aquarium practice without a single citable source. Treated as real but not as measurement.
AquariumHQ's overall position
The usual answer to 'what catfish can go in a Malawi tank', and it is a tolerable arrangement rather than a good one. The pleco lives in water harder than it wants and shares a food source with fish that out-compete it.
What would change it: Caves the cichlids cannot enter, and supplementary feeding for the pleco after lights out.
Factor by factor
- Water chemistryDerived
The pleco is a soft-water South American fish advised across 2–20 dGH and the cichlid a hard-water lake fish at 10–25. The overlap is real and the pleco is at the top of its tolerance in it. It is the animal being compromised.
- Armour and territoryReported
Bristlenose are reported as tolerating mbuna tanks better than most catfish, which is attributed to armour and to occupying caves rather than open ground. Damage to the pleco's fins is still commonly reported.
- Algae competitionDerived
Mbuna graze algae from rock and so does the pleco. In a tank kept clean enough for cichlids there may be little for either, and the pleco is the one that cannot supplement by hunting.
| Depends on | How much |
|---|---|
| Tank size and dimensions | significant |
| Life stage | none |
| The individual animal | significant |
How good is the overlap?
Whether two ranges intersect is a necessary condition, not evidence. What matters is WHERE the shared band sits: an overlap at the top of one animal's range and the bottom of the other's is a forced compromise however wide it looks, and it is the case a simple intersection test cannot see.
| Dimension | Assessment | What that means here |
|---|---|---|
| Temperature | Comfortable for both | The shared band 23–27 °C sits centrally in both ranges, with room to drift. |
| pH | Forced compromise — neither animal is where it wants to be | The shared band 7.6–7.8 pH sits at the top of one animal's range and the bottom of the other's. Both would be kept at their limits to accommodate the other. |
| Hardness | Workable | The shared band 10–20 °dGH is usable, though it does not sit centrally for both animals. |
Forced compromise — neither animal is where it wants to be
Both animals would be kept at the edge of their ranges to accommodate the other. Nothing here is a recommendation; it is the arithmetic of two incompatible requirements meeting at a point.
Factor by factor
Every factor states what it rests on. Most are derived from the traits stored on both records — sound arithmetic on AquariumHQ's own data, and not a report about how the pairing actually goes. Where a factor says 'not known', the data is missing and saying so matters, because a missing factor and a favourable one look identical once both are absent.
| Factor | Basis | Finding |
|---|---|---|
| Temperature | Derived from stored traits | Comfortable for both. The shared band 23–27 °C sits centrally in both ranges, with room to drift. |
| pH | Derived from stored traits | Forced compromise — neither animal is where it wants to be. The shared band 7.6–7.8 pH sits at the top of one animal's range and the bottom of the other's. Both would be kept at their limits to accommodate the other. |
| Hardness | Derived from stored traits | Workable. The shared band 10–20 °dGH is usable, though it does not sit centrally for both animals. |
| Body size | Derived from stored traits | Adult sizes are comparable at about 15 cm and 13 cm, so neither is a mouthful for the other. |
| Predation | Derived from stored traits | Highest predation risk in either direction is "moderate". |
| Territoriality | Derived from stored traits | Strongest territoriality across the pair is "strong". |
| Breeding aggression | Derived from stored traits | Breeding aggression reaches "strong". A pairing peaceful for months can change within a day of a spawn. |
| Fin-nipping | Derived from stored traits | No nipper-and-target combination between these two. |
| Aggression | Derived from stored traits | Strongest intraspecific aggression across the pair is "strong". It bears on the pairing because a fish under pressure from its own kind redirects. |
| Social requirements | Derived from stored traits | Electric yellow cichlid needs at least 4. A shoaling species held below its threshold shows chronic stress and, in several species, increased aggression towards tankmates. |
| Group-size dependency | Derived from stored traits | The outcome depends on group size as much as on the pairing: under-grouped shoalers nip more and hide more. |
| Tank zone | Derived from stored traits | The two use different levels of the tank, which reduces direct competition for space. |
| Activity level | Derived from stored traits | Activity levels are compatible. |
| Food competition | Derived from stored traits | Different feeding strategies, so direct competition is limited. |
| Risk to shrimp and snails | Derived from stored traits | Highest risk either animal poses to dwarf shrimp or snails is "near-certain". |
| Effect on plants | Derived from stored traits | Electric yellow cichlid eats plants, which constrains the aquascape rather than the pairing. |
| Tank dimensions | Derived from stored traits | The more demanding of the two needs at least 250 L and 120 cm of length before anything else is in the tank. Volume alone does not describe a home for a fish that swims in straight lines. |
| Life stage | Evidence-backed | Life-stage dependency: none. See the documented record. |
| Individual variation | Evidence-backed | Individual variation: significant. |
Environmental overlap
| Parameter | Shared range | Reading |
|---|---|---|
| Temperature | 23–27 °C | Aim for the middle of the shared band. |
| pH | 7.6–7.8 | Stability matters more than the exact figure. |
| Hardness | 10–20 °dGH | Check your source water before committing. |
What this assessment cannot tell you
- Individual temperament varies, particularly in cichlids and in bettas, and can override a favourable verdict for Bristlenose pleco or Electric yellow cichlid.
- The assessment is for the pair in isolation. A third species can change the outcome in either direction.
- Both animals are assessed at adult size, not at the size they are sold.
- A verdict is a statement about probability, not a guarantee.
Where the two water bands meet
Derived from the ranges AquariumHQ publishes for each species. The compatibility engine reads the same numbers; this is what they look like drawn on one axis.
Temperature (°C)
Scale: 0 to 36 °C.
pH (pH)
Scale: 4 to 9.5 pH.
Hardness (°dGH)
Scale: 0 to 30 °dGH.
Why the bands sit where they do
The overlap above is arithmetic. This is where the two numbers came from — the kind of water each animal is recorded from, and how much room that leaves.
These two animals come from different kinds of water, and that is where the arithmetic below comes from rather than from anything about their temperaments.
Bristlenose pleco
Lowland floodplain
40–300 µS/cm · still flow · low oxygen
Electric yellow cichlid
Lake Malawi
the rocky shore of Lake Malawi
200–280 µS/cm · low flow · near saturation oxygen
- TemperatureBristlenose pleco 22–27°CElectric yellow cichlid 23–28°C
Both inside their range from 23–27°C — 80% of the narrower animal’s range.
A wide window. Both animals are inside their own range across most of it, and the tank can be run without either sitting at an edge.
- pHBristlenose pleco 6–7.8Electric yellow cichlid 7.6–8.6
Both inside their range from 7.6–7.8 — 20% of the narrower animal’s range.
Barely an overlap. Whatever is chosen, at least one animal spends its life at the limit of its published range — which is survivable and is not the same as suitable.
- General hardnessBristlenose pleco 2–20 dGHElectric yellow cichlid 10–25 dGH
Both inside their range from 10–20 dGH — 67% of the narrower animal’s range.
A wide window. Both animals are inside their own range across most of it, and the tank can be run without either sitting at an edge.
Computed from the ranges AquariumHQ publishes for each species, each of which records what it rests on — a source value, a habitat inference, a physiological requirement or a trade convention. Most are habitat inferences, and the species pages say which.