How to Take Care of Mollies & Goldfish

Mollies and goldfish are fun to watch and easy to care for.

Mollies and goldfish are low-maintenance freshwater fish commonly sold in pet stores. Though many pet parents expect aquarium fish to have a short life span, mollies and goldfish can live up to 10 years or longer with the proper care. Pet fish may grow unhealthy and die when placed in overcrowded or polluted conditions, or as a result of temperature shock. You can avoid these problems with inexpensive supplies and routine maintenance.

Things You'll Need

• Aquarium
• Algae scrubber
• White vinegar
• Gravel
• Plate
• Aquarium thermometer
• Aquarium heater
• Aquarium filter
• Aquarium plants
• Fish food
• Fish net
• Aquarium vacuum

Instructions

Setting Up the Tank

1. Clean your aquarium and gravel in preparation for new fish. Scrub the sides of the tank with an aquarium-approved algae scrubber. Scrub gravel and decorative items with an algae scrubber. Remove stubborn buildup by submerging items in a 5 percent solution of white vinegar and water. Rinse the tank, gravel and decorative items thoroughly with aged water before using them.

2. Age water for use in the aquarium. Aged water is water set in a container at room temperature for 48 hours or more. Aging water removes chlorine, which can kill fish, and also reduces shock by preventing rapid changes in temperature. Always age water for 48 hours or more before introducing fish to a new tank or changing tank water.

3. Place three inches of gravel in the bottom of the tank. Place a plate over the gravel to prevent water from disturbing it, and slowly fill the tank with aged tap water. Remove the plate and add clean decorative aquarium-approved items if you wish.

4. Place an aquarium thermometer in the tank to monitor water temperature. Water temperature should stay between 75 and 80 degrees. Add an aquarium heater if you keep your home warmer or cooler than the recommended temperature.

5. Add an aquarium filter to reduce the frequency of changing water. Aquarium filters are not necessary for tanks smaller than 5 gallons or or tanks with few fish.

6. Place the tank on a stable surface out of direct sunlight. Direct sunlight can cause excessive algae growth and may overheat the tank. Turn on aquarium components and let them run for at least 24 hours before adding live animals.

Purchasing and Caring For Your Fish

1. Purchase mollies and goldfish at a reputable pet store. Examine fish to ensure healthy activity, scales, eyes and gills. Pick out specific fish for your tank. To prevent overcrowding, only add 1 inch of fish per 1 gallon of water. Do not count tails in this measurement. While at the pet store, consider purchasing catfish to feed on bottom debris and keep the tank clean.

2. Purchase fish food specifically marked for use with goldfish or mollies. Goldfish eat commercial fish flakes, while mollies eat algae, flakes and live blood worms, brine shrimp, fruit flies and black worms.

3. Purchase aquarium plants to create a natural environment for the fish. Add one plant per gallon of water. Banana plants, hornwort and other freshwater plants sold in the fish section work well in aquariums.

4. Add plants to the gravel at the bottom of the aquarium. Place them with the crown above the gravel.

5. Place the unopened pet store bag in your tank of aged water for 15 minutes to equalize the temperature and prevent shocking the fish. Open the bags after this period to release the fish.

6. Feed the fish only as much as they will eat in 5 minutes. One small pinch of food per fish is usually sufficient for small breeds. Excessive food can pollute and cloud the tank.

7. Clean the tank and replace 1/3 of the water every two weeks and whenever the tank looks cloudy: vacuum the aquarium bed with a gravel siphon into an empty bucket and replace vacuumed water with fresh, room temperature aged water. Use your hands or an aquarium net to remove any floating debris. Check the filter and replace any worn out components.

8. Replace all water whenever a fish dies: Remove fish with a net and place them in a plastic bag with water from the aquarium. Rinse off plants and place them in a bag with water. Dump out old water, clean the gravel, filter and tank interior, and refill with aged water. Replace plants and float the bags with the fish over the water for 15 minutes before releasing the fish in the tank.

Tips & Warnings

• Always have a separate tank of aged water available to use in case of emergencies.

• Remove fish immediately after death and trim off any diseased plant parts as soon as you notice them. Bacteria from dead or diseased fish and plants can contaminate other aquarium life.

• Mollies may nip long, flowing fins of other fish.

• Remove small fish and place them in a plastic bag with aquarium water when using a siphon to prevent them from being sucked up.

References

• Purdue University; Planting Your Aquarium; B. Rosie Lerner and Michael N. Dana; April, 2001
• FossWeb: Goldfish and Guppies
• Florida Museum of Natural History; Sailfin Molly; Robert H. Robins
• Hartz: Aquarium Cleaning
• Aquatic Community: Molly Fish
• Aquatic Community: Goldfish