Neon tetra and Zebra danio
Can these two share a tank? The assessment below is derived from stored behavioural and environmental traits, not from a compatibility chart.
Requirements align and no behavioural conflict is expected.
- Minimum volume
- 90 L
- Minimum length
- 75 cm
- Factors considered
- 6
Why it can work
- Temperature requirements overlap comfortably at 20–25 °C, with room for both animals to sit inside their preferred range.
- pH requirements overlap at 6–7.5.
- Hardness requirements overlap at 2–10 °dGH.
- Neon tetra needs a group of at least 8. 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.
- Zebra danio needs a group of at least 8. 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.
Conditions
Most interesting pairings are conditional on something. These are the things the keeper can actually change.
- At least 8 Neon tetra, counted as one group
- At least 8 Zebra danio, 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
A pairing that looks obvious and is a quiet thermal compromise. Both are sold as beginner community fish and their ranges overlap only at the edges.
Factor by factor
- Thermal overlap is narrow and edge-placedDerived
The danio's range runs cool and the neon's runs warm. They meet, and they meet at the top of one range and the bottom of the other.
- Activity mismatchReported
Danios are relentlessly active and are consistently reported to unsettle slower shoalers in tanks that do not give the danios room to run.
| Depends on | How much |
|---|---|
| Tank size and dimensions | significant |
| 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.
| Dimension | Assessment | What that means here |
|---|---|---|
| Temperature | Comfortable for both | The shared band 20–25 °C sits centrally in both ranges, with room to drift. |
| pH | Workable | The shared band 6–7.5 pH is usable, though it does not sit centrally for both animals. |
| Hardness | Workable | The shared band 2–10 °dGH is usable, though it does not sit centrally for both animals. |
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 20–25 °C sits centrally in both ranges, with room to drift. |
| pH | Derived from stored traits | Workable. The shared band 6–7.5 pH is usable, though it does not sit centrally for both animals. |
| Hardness | Derived from stored traits | Workable. The shared band 2–10 °dGH is usable, though it does not sit centrally for both animals. |
| Body size | Derived from stored traits | Adult sizes are comparable at about 3.5 cm and 5 cm, so neither is a mouthful for the other. |
| Predation | Derived from stored traits | Highest predation risk in either direction is "none". |
| Territoriality | Derived from stored traits | Neither animal holds a territory. |
| 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 "none". It bears on the pairing because a fish under pressure from its own kind redirects. |
| Social requirements | Derived from stored traits | Neon tetra needs at least 8; Zebra danio needs at least 8. 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 | Evidence-backed | Activity levels are compatible. Reported: Danios are relentlessly active and are consistently reported to unsettle slower shoalers in tanks that do not give the danios room to run. |
| 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 "moderate". |
| 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 90 L and 75 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: minor. |
Environmental overlap
| Parameter | Shared range | Reading |
|---|---|---|
| Temperature | 20–25 °C | Aim for the middle of the shared band. |
| pH | 6–7.5 | Stability matters more than the exact figure. |
| Hardness | 2–10 °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 Neon tetra or Zebra danio.
- 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.