What fish can live with Molly?

Usually safer companions on this hub include Platy. Open each pair check before you buy — the list is a shortlist, not a guarantee.

What tank mates should you avoid with Molly?

Avoid Betta, Jack Dempsey, Oscar based on size, temperament, or predation risk on this profile.

What size tank do Molly need for a community?

100L+ for short-fins; sailfins want 200L+. Their bulk and waste output need real volume and strong filtration.

Molly tank mates

Molly tank mates fail on chemistry before temperament. Sailfin females push serious bioload, so size the filter for the molly, not the neon average, and keep hard alkaline water. Soft-water tetras look peaceful in the aisle and leave one species outside its band at home. Usually safer: platies that share the hard-water lane. Caution on this hub covers guppies, swordtails, cories, and bettas when space or fins collide; oscars and jack dempseys are avoid. Give the group roughly 80L or more, keep the water hard, and treat every new name as a pair check — not a second starter-kit sticker.

Our first pick

Platy. Platies want the same hard water and the same temperature band, at a size that never competes with an adult molly. Run the pair check →

Common mistakeMixing mollies with soft-water tetras such as neons or cardinals is the stocking chart mistake that looks fine for a week. Molly water wants hard, alkaline stability; that chemistry stresses soft-water fish even when everyone is eating. Build a livebearer-heavy hard-water tank, or skip mollies — do not split the difference in one box. Salt is not a patch for soft tap water.

Evidence: verified

Confidence: high

Each name below opens a pair check with Molly. That check is the decision, not the list itself.

← Full Molly profile·Compatibility checker·Tank builder·More livebearer

Usually safer companions

Conservative shortlist from this profile. Open a pair page before you buy.

Platy Pair check
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.

Risky or situational

May work with more water, a mature system, or a species-only setup. Read the pair page before you experiment.

Nothing extra listed beyond the safer list.

Fish to avoid with Molly

Predation, aggression, or space rules on this profile. Treat these as poor default mixes.

Betta See why (pair)
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 See why (pair)
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.
Oscar See why (pair)
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.

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

Start a pair check with Molly, or open a starter plan with the top safer companions in the builder.

Open pair checker Open this plan in builder

Tank hubs: 80L

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.

Filter size guide →Heater size guide →Tank setup checklist →Beginner plants guide →

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.

Featured compatibility checks

Curated pair pages for Molly. Each opens a full verdict — not just a list label.

Molly tank mates — quick answers

What fish can live with Molly?: Usually safer companions on this hub include Platy. Open each pair check before you buy — the list is a shortlist, not a guarantee.
What tank mates should you avoid with Molly?: Avoid Betta, Jack Dempsey, Oscar based on size, temperament, or predation risk on this profile.
What size tank do Molly need for a community?: 100L+ for short-fins; sailfins want 200L+. Their bulk and waste output need real volume and strong filtration.