Blue rainbowfish
Melanotaenia caerulea
easypeacefulmiddle swimmerMelanotaeniidae
- Tank length
- 100 cmabout 3 ft (39 in)
- Group
- 6+
- Temperature
- 24–30 °C75–86 °F
- pH
- 7.4–8.2
- Adult size
- 6.7 cm2.6 in
- Lifespan
- 5–8 yrs
A large, fast rainbow that needs a long tank; buy several fish because males show best when competing with each other.A large, fast rainbow that needs a long tank; buy several fish because males show best when competing with each other.
Tank sizes
Good tankmates
Avoid with
- Black kuhli loach
No shared pH rangeNo shared pH range
- Brilliant rasbora
No shared pH rangeNo shared pH range
- Eastern rainbowfish
No shared pH rangeNo shared pH range
- Emerald eye rasbora
No shared pH rangeNo shared pH range
Lambchop rasboraNo shared pH rangeNo shared pH range
- Melon barb
No shared pH rangeNo shared pH range
- New Guinea rainbowfish
No shared pH rangeNo shared pH range
- Panda garra
No shared pH rangeNo shared pH range
- Panda tetra
No shared pH rangeNo shared pH range
Salt and pepper coryNo shared pH rangeNo shared pH range
- Ticto barb
No shared pH rangeNo shared pH range
- Adolfo's cory
No shared pH rangeNo shared pH range
Data used by the planner
| Temperature | 24–30 | AqAdvisor (aqadvisor.com), retrieved 2026-10-04 · medium confidence |
|---|---|---|
| pH | 7.4–8.2 | AqAdvisor (aqadvisor.com), retrieved 2026-10-04 · medium confidence |
| Hardness (dGH) | 5–20 | AqAdvisor (aqadvisor.com), retrieved 2026-10-04 · medium confidence |
| Origin | Southern Papua New Guinea (Purari and Kikori drainages) | curated-v0 (needs expert review) · low confidence |
| Beginner friendly | Yes | curated-v0 (needs expert review) · medium confidence |
| Care level | easy | curated-v0 (needs expert review) · medium confidence |
| Activity | active | curated-v0 (needs expert review) · medium confidence |
| Swimming level | middle | curated-v0 (needs expert review) · medium confidence |
| Temperament | peaceful | curated-v0 (needs expert review) · medium confidence |
| Nips fins | No | curated-v0 (needs expert review) · medium confidence |
| Long fins | No | curated-v0 (needs expert review) · medium confidence |
| Territorial | No | curated-v0 (needs expert review) · medium confidence |
| Lives in groups | Yes | curated-v0 (needs expert review) · medium confidence |
| Minimum group | 6 | curated-v0 (needs expert review) · medium confidence |
| Diet | omnivore | curated-v0 (needs expert review) · medium confidence |
| Lifespan (years) | 5–8 | curated-v0 (needs expert review) · low confidence |
| Months to adult size | 12 | curated-v0 (needs expert review) · low confidence |
| Safe with plants | Yes | curated-v0 (needs expert review) · medium confidence |
| Minimum tank length | 100 | curated-v0 (needs expert review) · medium confidence |