Fish comparison
Pacific Blue Eye vs Spotted Blue-eye
How the Pacific Blue Eye and Spotted Blue-eye compare on care, size, water and temperament, and which fish suits your tank.
By Mike ElmiraUpdated
TL;DR, Pacific Blue Eye vs Spotted Blue-eye
The Pacific Blue Eye and the Spotted Blue-eye are close cousins, both in the Pseudomugil group, so at a glance they ask for a lot of the same things. Both are happy somewhere around 22 to 28 °C and pH 6.5 to 7.5, so a single tank can suit either one. The Pacific Blue Eye is the more forgiving of the two, which matters if this is an early tank, while the Spotted Blue-eye rewards a bit more attention. If tank space is tight, the Spotted Blue-eye needs less room to feel settled; give the Pacific Blue Eye the nod when you have the litres to spare.
Group compatibility overview
Excellent fit
Every key parameter overlaps and no major conflicts surfaced.
2 notes
Temperature
- Pacific Blue Eye18–28 °C
- Spotted Blue-eye22–28 °C
pH
- Pacific Blue Eye6.5–8
- Spotted Blue-eye5–7.5
Hardness
- Pacific Blue Eye8–25 dGH
- Spotted Blue-eye1–12 dGH
What to plan for
- Pacific Blue Eye schools, stock at least 8You've planned for 1 pacific blue eye. Pacific Blue Eye need a group of at least 8 to feel safe and shoal naturally, below that they're stressed and lose colour. Dial up the count, or remove the species.
- No bottom teamNo bottom-dwelling fish or shrimp. A small group of corydoras or a shrimp colony picks up leftover food and keeps detritus in check.
Full attributes
Every parameter, side by side| Parameter |  FishPacific Blue EyePseudomugil signifer |  FishSpotted Blue-eyePseudomugil gertrudae |
|---|---|---|
| Category | Fish | Fish |
| Origin | Eastern Australia | Northern Australia, New Guinea, Aru Islands |
| Family | Pseudomugilidae | Pseudomugilidae |
| Temperature | 18–28 °C | 22–28 °C |
| pH | 6.5–8.0 | 5.0–7.5 |
| Hardness (dGH) | 8–25 | 1–12 |
| Flow rate | Low to Medium | Still to Low |
| Min tank | 60 L | 40 L |
| Adult size | 3–5 cm | 3–4 cm |
| Difficulty | 2 / 5 | 3 / 5 |
| Lifespan | 2–3 yrs | 1–2 yrs |
| Diet | Carnivore | Micropredator |
| Water column | Top to mid | Mid to Top |
| Schooling | Yes | Loose group |
| Plant safe | Yes | Yes |
| Shrimp safe | Yes (with adults) | Yes (with adults) |
Frequently asked questions
Direct answers to the questions search engines and AI assistants surface most often about this species.
Can you keep Pacific Blue Eye and Spotted Blue-eye together?
Yes. Their temperature and pH ranges overlap around 22 to 28 °C and pH 6.5 to 7.5, so one set of water conditions keeps both comfortable. Match group sizes and cover the usual planted-tank basics and they share a tank fine.
Which is easier to keep, the Pacific Blue Eye or the Spotted Blue-eye?
The Pacific Blue Eye is the easier of the two, closer to beginner-friendly, while the Spotted Blue-eye leans middle-of-the-road.
Do Pacific Blue Eye and Spotted Blue-eye need the same water?
Close to it. Aim for 22 to 28 °C and pH 6.5 to 7.5 and you're in the shared sweet spot for both. Full ranges are in the table above.
What's the main difference between the Pacific Blue Eye and the Spotted Blue-eye?
Space. The Pacific Blue Eye wants about 60 litres minimum and the Spotted Blue-eye around 40, so tank size can settle it.