
Freshwater Fish
Molly.
A hardy livebearer that looks sharp against a planted tank and grazes algae as it goes. Beginner-easy and peaceful; mollies like hard water with a little salt tolerance and will happily breed in a 20-gallon-plus community. Available in several color and finnage forms.
We keep this species at our Erie store. Come and see it in the tanks, or call (814) 456-9445 and ask what we have in right now.
Sea Cave keeps this species. You will find these in the tanks at 660 East 14th Street in Erie. We never ship live animals.
- Condition
- new
- Fulfillment
- Local pickup — Erie, PA
We never ship fish, coral, or invertebrates — every animal here is one you meet in person. Each one is acclimated and health-checked in-house before it goes out into the display tanks. This is a species we keep, and what is swimming on any given day changes with the deliveries, so please call (814) 456-9445 before you drive in.
Care at a glance
What to know before you take one home.
- Care level
- Beginner
- Temperament
- Peaceful
- Community
- Community safe
- Adult size
- 3.5"
- Min tank size
- 20 gallons
- Diet
- Omnivore
- Scientific name
- Poecilia spp.
Good tank mates
Black mollies are peaceful, community-safe livebearers that mix well with other calm fish of a similar size. Good categories: other livebearers (platies, guppies, swordtails), small peaceful tetras and rasboras, and corydoras catfish. A few real examples: platies, harlequin rasboras, and bronze cory cats. Avoid fin-nippers like tiger barbs, aggressive cichlids, and any fish big enough to eat a molly. Because mollies like hard water with a little salt tolerance, pick tankmates comfortable in those same conditions.
Good to know
Black mollies are livebearers, meaning they give birth to free-swimming young rather than laying eggs.
What is in the tanks and each animal's temperament vary — call (814) 456-9445 for pairing advice.
Good tankmates
Plays well with.
Species we’d keep in the same tank, with why each pairing works. What is in the tanks and each animal’s temperament vary — call (814) 456-9445 for advice on pairing.
New to stocking a tank? Read our guide on which fish live together.

Assorted Guppy
Fellow livebearer in the same genus family with nearly identical water chemistry preferences (pH 7.5–8.5, hard alkaline water, 75–82°F). Both species are well-documented community fish. Minor risk that mollies may occasionally investigate fancy guppy tails, but this is manageable with adequate tank size and is not a consistent aggression pattern.

Assorted Platy
Peaceful livebearer sharing the molly's hardwater and alkaline preference. No aggression, predation, or parameter incompatibility concerns. A textbook community pairing supported across multiple reputable sources.

Bronze Cory
Captive-bred Corydoras tolerate pH 7.0–8.0 and moderate hardness, which overlaps with the lower end of molly parameters. They occupy the bottom of the water column, avoiding direct competition. Aquarium Co-Op explicitly lists them as a top molly tankmate. A compromise parameter around pH 7.5 and moderate hardness works for both.
- S
Swordtail
Peaceful livebearer with water parameter requirements (hard, alkaline water, 72–82°F) closely matching the molly's. Similar size and temperament make coexistence straightforward in a community setup.
Visit the store
660 East 14th Street,
Erie, PA.
Mon–Fri 12–6 · Sat 11–4 · Sun closed. Call ahead on livestock — what's on the floor rotates.