Cherry shrimp and Red-tailed black shark
Can these two share a tank? The assessment below is derived from stored behavioural and environmental traits, not from a compatibility chart.
Can work, but only if the stated conditions are met.
- Minimum volume
- 245 L
- Minimum length
- 150 cm
- Factors considered
- 7
Concerns
Red-tailed black shark may take adult shrimp, particularly while the shrimp are moulting or newly added.
Derived from: traits.predation.adultDwarfShrimp
Temperature requirements overlap at 22–27 °C, though the band does not sit centrally for both animals. Aim for the middle of it and keep the heater accurate.
Derived from: environment.temperature on both records
Red-tailed black shark 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
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 6.5–7.8.
- Hardness requirements overlap at 6–15 °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.
- Dense cover — moss, leaf litter or a shrimp-safe refuge the fish cannot enter
- At least 10 Cherry shrimp, counted as one group
- At least 245 L with a footprint of 150 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
Limited evidence
Some reports exist and they do not agree, or there are too few to generalise from. Read the derived assessment as the main basis.
AquariumHQ's overall position
Conditional with low confidence, and the honest answer is that AquariumHQ does not know. Outcomes vary between individual sharks rather than between tanks: an established colony in a heavily planted tank frequently survives, a new colony in an open tank frequently does not, and which of those a keeper has is only half of what decides it.
Factor by factor
- Predation on adult shrimpReported
Reports are inconsistent, and that inconsistency is itself what is widely reported. The shark is an omnivore working the same surfaces the shrimp graze, and outcomes range from indifference to a colony disappearing over a month. There is not enough agreement to generalise from.
- ShrimpletsDerived
Newly released shrimplets are taken by almost anything that forages the substrate. A colony can persist through this where cover is dense enough; a small population usually does not.
- Territorial disturbanceDerived
The shark patrols the floor continuously, which is the surface the shrimp use. Even where nothing is eaten the shrimp are displaced from the best grazing.
| Depends on | How much |
|---|---|
| Tank size and dimensions | significant |
| Life stage | minor |
| The individual animal | decisive |
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 | Workable | The shared band 22–27 °C is usable, though it does not sit centrally for both animals. |
| pH | Comfortable for both | The shared band 6.5–7.8 pH sits centrally in both ranges, with room to drift. |
| Hardness | Comfortable for both | The shared band 6–15 °dGH sits centrally in both ranges, with room to drift. |
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 | Workable. The shared band 22–27 °C is usable, though it does not sit centrally for both animals. |
| pH | Derived from stored traits | Comfortable for both. The shared band 6.5–7.8 pH sits centrally in both ranges, with room to drift. |
| Hardness | Derived from stored traits | Comfortable for both. The shared band 6–15 °dGH sits centrally in both ranges, with room to drift. |
| Body size | Derived from stored traits | Red-tailed black shark reaches about 15 cm against 4 cm for Cherry shrimp — a ratio of 3.8. Size disparity drives opportunistic predation independently of temperament. |
| Predation | Evidence-backed | Highest predation risk in either direction is "moderate". Reported: Reports are inconsistent, and that inconsistency is itself what is widely reported. The shark is an omnivore working the same surfaces the shrimp graze, and outcomes range from indifference to a colony disappearing over a month. There is not enough agreement to generalise from. |
| Territoriality | Derived from stored traits | Strongest territoriality across the pair is "strong". |
| Breeding aggression | Derived from stored traits | Neither becomes notably more aggressive while spawning. |
| 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 | 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 "high". |
| 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 180 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: minor. Reports are inconsistent, and that inconsistency is itself what is widely reported. The shark is an omnivore working the same surfaces the shrimp graze, and outcomes range from indifference to a colony disappearing over a month. There is not enough agreement to generalise from. |
| Individual variation | Evidence-backed | Individual variation: decisive. |
Environmental overlap
| Parameter | Shared range | Reading |
|---|---|---|
| Temperature | 22–27 °C | Aim for the middle of the shared band. |
| pH | 6.5–7.8 | Stability matters more than the exact figure. |
| Hardness | 6–15 °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 Red-tailed black shark.
- 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.
Cherry shrimp
Subtropical stream
100–500 µS/cm · moderate flow · near saturation oxygen
Red-tailed black shark
Hill stream and rapids
50–300 µS/cm · high flow · near saturation oxygen
- TemperatureCherry shrimp 18–27°CRed-tailed black shark 22–27°C
Both inside their range from 22–27°C — 100% 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.
- pHCherry shrimp 6.5–8Red-tailed black shark 6.5–7.8
Both inside their range from 6.5–7.8 — 100% 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.
- General hardnessCherry shrimp 6–15 dGHRed-tailed black shark 5–15 dGH
Both inside their range from 6–15 dGH — 100% 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.