Fishes / Habitat

Mollies: The Livebearer That Wants Salt in Its Water

The molly, Poecilia sphenops, is a chunkier livebearer native to Central America, popular across India in its black, silver and dalmatian-spotted forms. Adults reach ten to twelve centimetres, conside

Close-up of a colorful blue cichlid fish swimming in a lush freshwater aquarium.
Photo by Sóc Năng Động on Pexels
In this guide

Overview

The molly, Poecilia sphenops, is a chunkier livebearer native to Central America, popular across India in its black, silver and dalmatian-spotted forms. Adults reach ten to twelve centimetres, considerably larger than a guppy, with a rounded body and a sail-like dorsal fin in the lyretail varieties.

Mollies are unusual among common aquarium fish in that they genuinely do better with a pinch of aquarium salt or even brackish water, reflecting their natural habitat in coastal and estuarine waters.

Worth knowing before you shop: most black and dalmatian mollies sold in Indian pet shops are not pure Poecilia sphenops but hybrids between several closely related molly species developed over generations of breeding, so exact parentage is rarely traceable. This does not affect their care, only their pedigree.

Tank and water requirements

A single molly needs at least sixty litres, more if kept in the small groups they prefer. They like harder, more alkaline water than many tropicals, which again suits typical Indian tap water well, and benefit from a tablespoon of aquarium salt per ten litres.

Good filtration matters more with mollies than with guppies, since they are heavier feeders and produce more waste. A temperature of twenty four to twenty eight degrees suits them across most of the country.

Diet and behaviour

Mollies are largely herbivorous grazers in the wild, so their diet should lean towards spirulina flakes, blanched vegetables such as courgette or spinach, and algae wafers, alongside the occasional protein treat. A diet too heavy in protein alone often leads to bloating.

They are peaceful but can be fin nippers if underfed or kept in cramped conditions, and males can pester females persistently, so a ratio of two or three females to each male keeps the peace.

Buying tips

  • Black mollies and dalmatian mollies are the most widely stocked varieties in Indian pet shops
  • Balloon mollies, bred for a rounded belly shape, are controversial among hobbyists due to the spinal deformity involved and are best avoided
  • Prices typically range from thirty to a hundred rupees per fish for common varieties

Article content © Ravi Teja. All rights reserved.

A little more to explore.

Close-up of a colorful blue cichlid fish swimming in a lush freshwater aquarium.

Fishes / Habitat

Scissortail Rasbora: An Active Fish With a Forked Signal

The scissortail rasbora, Rasbora trilineata, gets its name from the black-and-white banded tail fin, which opens and closes in a scissoring motion as the fish swims, a genuinely visible behaviour rath

2 min read

Two bright goldfish swimming gracefully in a richly planted aquarium.

Fishes / Behaviour

Why You Should Never Flush a Dead (or Unwanted) Fish

Flushing a fish, whether dead or simply unwanted, down the toilet is a habit many Indian households have inherited without questioning it, and it carries real risks that are worth understanding.

2 min read

Colorful coral reef with diverse marine life in a vibrant underwater aquarium scene.

Fishes / Getting Started

Types of Aquarium Covers for a Saltwater Tank

A cover might seem like an afterthought compared to filtration or lighting, but for a saltwater tank it does real, unglamorous work: cutting evaporation, which matters a great deal given how salinity

2 min read