Molly Care Sheet



Molly, photo by h080
  • Scientific Name: Poecilia sphenops
  • Lifespan: Approximately 3-5 years if proper care is given
  • Size: Up to 6 inches
  • Care: Easy
  • Community: Yes, as long as you have lots of room for them to move around. (5-7 mollies per 10 gallons)
  • Lifestyle: Diurnal, active during the day.

Tank Requirements

  • Minimum Tank Size: 20 gallon tank, bigger is always better.
  • Water Temperature Range: 76 – 82 °F
  • Water pH Range: 7.5 – 8.5
  • Water Hardness Range: 15-30 dGH

Perform a 10%-25% water change weekly. If you do not have a filter in your tank, do a water change twice a week.


A hood is recommended as it aids in helping your fish stay in the tank. Also, the hood keeps debris or dust from falling into the tank.


For Lighting: Full spectrum lighting – T5 is recommended.


Every fish and tank is different, so it is important to know what you’re dealing with. Some fish love a lot of current and others love no current at all like bettas. Some fish tanks are tiny and some are huge. Knowing what you have, or what you are going to have will help aid you in deciding which filter to go with. Check this article here to select which filter you should go with.


Silk fake plants, live plants, and decorative ornaments may be put into a molly’s tank. If choosing to use live plants, be aware that Black moor’s love to eat plants and may destroy your plants in doing so. If choosing to use fake plants, try to use mainly silk fake plants which are smoother for the molly’s skin. Some fake plants are very rough and can scrape the sides of your molly’s skin if rubbed the wrong way. This is just something to take into consideration when going plant shopping.


Since Molly’s are omnivores, they should be fed a high quality flake food, and a variety of vegetables. Their favorite vegetables are blanched zucchini medallions, cucumber medallions and shelled peas. If you don’t have the time to cut and blanch vegetables, then a spirulina based pellet or flake can take the place of plant matter in their diet. As a treat every once in a while, you may feed them bloodworms, daphnia, and brine shrimp.


You are going to want to go with something that is easy to clean and is safe for your molly. Most people prefer to use sand rather than gravel due to the impaction gravel may cause if ingested. However, if gravel is the way you want to go, make sure to use very fine gravel that will not harm your molly if ingested or you may choose to use large gravel pieces that can’t even fit in your molly’s mouth. River stones are another option you may choose due to the fact that river stones are bigger than the goldfish’s mouth so therefore can not be ingested. But have in mind, cleaning will be a lot harder since you will have to manually pick up each river stone to clean the bottom of the tank.


Note: The information on this Molly care sheet is not a substitute for veterinary care.


  1. Mollies can get up to 6 inches, not four, so more like 20 gallons+ would be better, as unless your 10 gallon is pretty empty in the way of plants and decor, it can be stressful for the fish from overcrowding. 🙂

Leave a Reply