Compatibility brief
Can Brown / hockey-stick pencilfish live with Oscar?
Risky. This mix is commonly discouraged for typical setups.
Brown / hockey-stick pencilfish + Oscar: Aggression mismatch. Oscar is aggressive, while Brown / hockey-stick pencilfish is peaceful. The aggressive fish will likely bully or harm the peaceful one. Real tanks add variables Fishori cannot model; treat this as a high-risk read, not certainty.
Compatibility score
Profile confidence: medium
Order of checkstank volume vs adults → predation mouth gap → temperament / fin nipping → shared water windows.
300L
Combined minimum footprint reference for these two species: about 300L (larger active fish often want more length).
Oscar (35cm adult) may treat small Brown / hockey-stick pencilfish (~5cm) as food once grown — plan adult sizes, not shop sizes.
Brown / hockey-stick pencilfish (peaceful) and Oscar (aggressive) are far apart on aggression — bullying or injury is a common outcome in average community layouts.
Assessment details
Aggression mismatch
Top issueOscar is aggressive, while Brown / hockey-stick pencilfish is peaceful. The aggressive fish will likely bully or harm the peaceful one.
Oscar may eat Brown / hockey-stick pencilfish
Oscar (35cm) is predatory and Brown / hockey-stick pencilfish (5cm) is small enough to be eaten. This pairing is unsafe.
Compatible temperature range
Both fish can comfortably share similar water temperatures.
“Oscar is aggressive, while Brown / hockey-stick pencilfish is…”
Aggression mismatch
Next steps
Concrete changes, not "research more" filler.
- •Brown / hockey-stick pencilfish should be kept in a group of at least 6 for best health and behaviour.
Try instead
- →Brown / hockey-stick pencilfish should be kept in a group of at least 6 for best health and behaviour.
- →Build a species-only tank for the larger fish, or restock with fish too large to be eaten at adult sizes.
- Seriously Fish. Nannostomus eques
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Nannostomus eques
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Nannostomus eques
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
- Seriously Fish. Astronotus ocellatus
Primary: aquarium size, water chemistry, behaviour, and compatibility (URL verified in upgrade script; recheck if site content changes).
- FishBase. Astronotus ocellatus
Secondary: taxonomy, distribution, and maximum length in nature; cross-check with aquarium import lines and measured tank parameters.
- Wikipedia. Astronotus ocellatus
Secondary: general species context; verify all husbandry numbers against a dedicated aquarium care sheet and your test kit, not a single table row.
- Wikipedia. Astronotus ocellatus (oscar)
Encyclopaedia overview; use specialist aquarium sources for your stock's real temperature/pH/footprint needs.
Try this next
Build the full stocking list with Brown / hockey-stick pencilfish + Oscar
Plan further
Try both species in the full-stock tank check, or open either fish profile for mates lists. Methodology explains how verdicts are produced.
Individual fish vary in personality. Fishori uses conservative hobby rules. Observe any new introduction closely, feed thoughtfully, and keep a quarantine or backup plan. This is not veterinary advice.
Profile data confidence: high. Based on multiple reputable aquarium care sources with strong agreement.