Incompatible4 concerns

Cherry shrimp and German blue ram

Can these two share a tank? The assessment below is derived from stored behavioural and environmental traits, not from a compatibility chart.

VerdictIncompatiblehigh confidence

Should not be attempted. At least one factor is expected to cause harm.

Minimum volume: 105 L
Minimum length: 90 cm
Factors considered: 7

Concerns

majortemperature

The shared band 26–27 °C 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. 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.

Derived from: environment.temperature range position on both records

majorinvertebrate risk

German blue ram will take adult dwarf shrimp. Heavy planting reduces losses but does not prevent them; a shrimp colony will not establish.

Derived from: traits.predation.adultDwarfShrimp

minorbreeding aggression

German blue ram 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

minorzone competition

Both species occupy the bottom of the tank, so allow for the shared space when judging the footprint.

Derived from: zone and traits.activity on both records

Why it can work

pH requirements overlap at 6.5–7.2.
Hardness requirements overlap at 6–10 °dGH.
Cherry shrimp needs a group of at least 10. 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.

Conditions

Most interesting pairings are conditional on something. These are the things the keeper can actually change.

At least 10 Cherry shrimp, counted as one group

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

Environmental compatibility is the limiting factor before behaviour is reached: the ram's warmth is at the edge of what the shrimp want. Behaviourally the colony persists with cover and does not increase.

Factor by factor

Predation on shrimplets and small adultsReported
A dwarf cichlid takes shrimplets reliably and small adults opportunistically. A colony holds rather than grows, and only with heavy cover.
TemperatureDerived
The German blue ram wants water at the top of, or above, where a cherry shrimp colony breeds best. This is a forced compromise rather than a shared preference.

What the answer depends on. A single cell in a compatibility chart cannot hold any of these.
Depends on	How much
Tank size and dimensions	minor
Life stage	none
The individual animal	minor

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.

Each dimension assessed for the quality of the overlap, not merely its existence.
Dimension	Assessment	What that means here
Temperature	Forced compromise — neither animal is where it wants to be	The shared band 26–27 °C 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.
pH	One animal at the edge of its range	The shared band 6.5–7.2 pH sits at the top of one animal's range, so that animal is permanently at its limit even though the overlap looks generous.
Hardness	Workable	The shared band 6–10 °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.

3 evidence-backed16 derived0 not known

Factor	Basis	Finding
Temperature	Derived from stored traits	Forced compromise — neither animal is where it wants to be. The shared band 26–27 °C 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.
pH	Derived from stored traits	One animal at the edge of its range. The shared band 6.5–7.2 pH sits at the top of one animal's range, so that animal is permanently at its limit even though the overlap looks generous.
Hardness	Derived from stored traits	Workable. The shared band 6–10 °dGH is usable, though it does not sit centrally for both animals.
Body size	Derived from stored traits	Adult sizes are comparable at about 4 cm and 7 cm, so neither is a mouthful for the other.
Predation	Evidence-backed	Highest predation risk in either direction is "high". Reported: A dwarf cichlid takes shrimplets reliably and small adults opportunistically. A colony holds rather than grows, and only with heavy cover.
Territoriality	Derived from stored traits	Strongest territoriality across the pair is "mild".
Breeding aggression	Derived from stored traits	Breeding aggression reaches "moderate". 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 "mild". It bears on the pairing because a fish under pressure from its own kind redirects.
Social requirements	Derived from stored traits	Cherry shrimp needs at least 10. 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	Both occupy the bottom of the tank, so the shared space is under pressure.
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	Neither animal damages planting.
Tank dimensions	Derived from stored traits	The more demanding of the two needs at least 75 L and 60 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. A dwarf cichlid takes shrimplets reliably and small adults opportunistically. A colony holds rather than grows, and only with heavy cover.
Individual variation	Evidence-backed	Individual variation: minor.

Environmental overlap

Parameter	Shared range	Reading
Temperature	26–27 °C	Aim for the middle of the shared band.
pH	6.5–7.2	Stability matters more than the exact figure.
Hardness	6–10 °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 Cherry shrimp or German blue ram.
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.

The two species

Cherry shrimpNeocaridina davidiThe most forgiving dwarf shrimp in the hobby and the usual first one. Colour strains — red, yellow, blue, green, orange — are all the same species, which is why mixing them produces wild-type brown offspring within a few generations.German blue ramMikrogeophagus ramireziA small, brilliantly coloured dwarf cichlid that is far less hardy than its size suggests. It needs water above 26 °C and a mature, stable tank; commercially farmed stock is notably fragile and short-lived.