Molly tank mates
Bigger and messier than people expect. Hard alkaline water shifts which neighbours work. Soft-water tetras like neons do not pair.
Lists below are built from this species record (safest, best with, risky, unsafe) — each link opens a pair-level check, not a guarantee.
Best tank mates (on file)
Merged from conservative safest and best with fields — de-duplicated by species.
The Molly profile lists Corydoras Catfish as both safe and a recommended pairing. Corydoras Catfish schools in groups of 6 or more, so plan room for the whole group rather than one fish. Water parameters barely overlap between the two, so check the temperature and pH ranges on both profiles before stocking. Corydoras Catfish swims in the bottom zone while Molly stays in the middle, so the two will not crowd the same water column.
The Molly profile lists Guppy as both safe and a recommended pairing. Water parameters barely overlap between the two, so check the temperature and pH ranges on both profiles before stocking.
The Molly profile lists Platy as both safe and a recommended pairing. Platy is a peaceful beginner-care species with a 60L minimum. Run the pair checker for your specific tank before stocking.
The Molly profile lists Swordtail as both safe and a recommended pairing. Swordtail is a semi-aggressive beginner-care species with a 80L minimum. Run the pair checker for your specific tank before stocking.
Risky or situational
From risky tank mates and broad avoid with (excluding “unsafe” below). May work with species-only setups, more water, or mature systems — read the pair page.
None on file beyond the safe list.
Fish to avoid with Molly
From the unsafe list — predation, aggression, or space rules on this profile.
Oscar reaches 35cm and is flagged predatory. Molly at 10cm is prey-sized for it. Oscar needs at least 300L, far above the 80L minimum for Molly. The tank that houses one stresses the other. Oscar is rated aggressive and Molly is rated peaceful. No community-style planning carries that gap.
Betta conflicts with Molly on temperament, predation, or footprint. The juvenile size in a shop tank is not the figure that matters here.
Jack Dempsey reaches 25cm and is flagged predatory. Molly at 10cm is prey-sized for it. Jack Dempsey needs at least 200L, far above the 80L minimum for Molly. The tank that houses one stresses the other. Jack Dempsey is rated aggressive and Molly is rated peaceful. No community-style planning carries that gap.
Tank size and groups
- Published minimum for Molly: 80L — group minimum 3 .
- Compatibility changes when the tank is too short for turning, too little for a real school, or too warm for one species and not the other — that is why pair checks include tank context, not only temperament.
- Nearest litre hub to this minimum: 80L hub.
Plan before you buy
Pair checks for every mix, then multi-species stocking in the builder.
Filtration & heating
A 80L minimum tank for Molly needs a filter rated for at least 320L/hr turnover and a heater maintaining 24–30°C.
Similar fish (same category)
- Swordtail — min 80L
- Platy — min 60L
- Endler's Livebearer — min 40L
- Guppy — min 40L
- Sailfin Molly — min 120L
Related (care + temperament)
Other species that list Molly
Reverse lookup: these profiles reference Molly under safe or “best with” lists.