One of the most common freshwater fish in the aquarium hobby today, and quite often the most unusual, is the Black Molly.
Unlike the other types of Molly fish available in the fish keeping hobby, the Black Molly gets the majority of its traits as a result of captive breeding, and you would struggle to find one in the wild.
It’s pretty obvious where the Black Molly gets its name from, but what isn’t as obvious is how they came to obtain such a dark, distinct color.
Almost all black mollies will be born with a serious case of melanism, which is a skin condition opposite to albinism (the lack of color pigmentation).
While the majority of Black Molly fish are completely black, they can sometimes be found with a streak of yellow which runs down the dorsal fin, or a slightly silvery color on the flanks.
Black Mollies are relatively small in size, with the males growing to a maximum of 3 inches, and the females often growing a couple of inches larger.
Their lifespan will completely depend on how well they are cared for, but in the perfect scenario, Black Molly fish can live up to 5 years in captivity.
The optimal ratio that we recommend is 3 females to each male. Male Mollies are aggressive breeders, so providing more females will help divide the attention between them, to prevent any one female from receiving constant attention.
Failing to stick to this ratio, or one thereabouts, you may find that your females will become too stressed to eat, and could potentially die.
It is often thought that Black Mollies are best served in Brackish waters, but that’s not the case at all. While it’s true that they can survive in almost any water conditions, they will be better off kept in freshwater tanks.
Mollies love space to move, and since you should be keeping them in larger groups to prevent any unnecessary harassment or aggression, you will need a tank that is big enough to accommodate them.
At least 20 gallons should be the minimum, but if possible, a 45-gallon tank will be a lot better.
In terms of pH and temperature, we would recommend that you keep your Black Mollies in water that is between 70 and 80 degrees Fahrenheit, with a pH that is closer to the harder, more alkaline side of the spectrum (7.5 – 8.2).
Mollies are very sensitive to changes in water parameters, so it’s important that you keep the tank environment as consistent as possible.
Black Mollies love planted aquariums, so the more plants you have, the better. The plants will not only allow the adult fish to feel more comfortable, but they will also increase the survival rate of the fry.
Mollies are notorious when it comes to feeding on their fry, so giving them a place to hide will help your breeding efforts enormously. Pretty much any plants will do the trick, but here are a few of the ones we would recommend:
- Java Ferns
- Amazon Sword
- Java Moss
- Hygrophila