Goal #2:
Decorate the tank with plants, rocks, and space to swim so the fish feel safe and have fun exploring their home.

Goal #3:
Keep up with feeding and cleaning on a regular schedule to make sure the fish stay healthy—and take care of any baby fish if they’re born.

Other Names It Goes By:
Marbled Molly, Black Marbled Molly, or just Molly Fish

Scientific Name:
Poecilia sphenops

Description:
Tiger Mollies are freshwater fish known for their cool marbled pattern that looks kind of like tiger stripes, usually black mixed with silver, white, or orange. They come from warm, slow-moving rivers and coastal waters in Central America, especially in countries like Mexico and Honduras. Tiger Mollies are very active and social, which is why they like being in groups.

B.

1. The water is usually warm, between about 72 and 82 degrees Fahrenheit (22–28°C).

2. The water is slightly alkaline, which means it has a pH level around 7.5 to 8.5.

3. The water tends to be hard, meaning it has more minerals like calcium and magnesium than soft water.

C. In their natural environment, Tiger Mollies have plenty of space to swim in open water but also places to hide, like plants and rocks. They usually live in groups that spread out over a few feet or more in rivers and ponds, so they’re used to having room to move around.

B. If I go with a natural-colored aquarium gravel, it would cost about $10 to $20 per bag, and for a 30-gallon tank, I’d probably need 2 bags, which means the total cost would be around $20 to $40.

B. Yes, but not always for the fish. Tiger Mollies don’t need strong lighting, but if you have live plants, they do need light to stay healthy. Even if you don’t have plants, a basic light helps keep your tank looking nice and lets you check on your fish easily.

C. You should leave the light on for about 8 to 10 hours a day. Fish need rest too, so make sure to turn it off at night to give them a break. If you forget easily, a timer can help you turn the light on and off automatically.

B. You don’t have to have one, but it’s a good idea. Tiger Mollies can jump, and a hood keeps them safe. It also keeps your tank clean

B. Yes, I will need a water heater to keep the tank at the right temperature. Room temperature can change a lot, and if the water gets too cold, the fish can get sick or stressed. A heater helps keep the tank warm and steady, which is important for keeping Tiger Mollies healthy and happy.

Ex. AquaClear 30 or a Tetra Whisperer EX3O

To make sure they have enough oxygen, it’s important to have something in the tank that moves the water, like a filter or an air stone that makes bubbles. This helps mix oxygen into the water so the fish can breathe easily.

Seriously Fish. “Poecilia sphenops (Molly).” Seriously Fish, www.seriouslyfish.com/species/poecilia-sphenops/. Accessed 19 Aug. 2025.

Aquarium Source. “Tiger Molly Care Sheet.” Aquarium Source, www.aquariumsource.com/tiger-molly/. Accessed 19 Aug. 2025.

The Spruce Pets. “Tiger Molly Fish Care.” The Spruce Pets, www.thesprucepets.com/tiger-molly-fish-care-1378224. Accessed 19 Aug. 2025.

LiveAquaria. “Molly Fish (Poecilia sphenops).” LiveAquaria, www.liveaquaria.com/product/prod_display.cfm?c=470+472+642&pcatid=642. Accessed 19 Aug. 2025.

PetMD. “Molly Fish Care.” PetMD, www.petmd.com/fish/care/molly-fish-care. Accessed 19 Aug. 2025.