by Derek Lambert
Reading most books and articles on Mollies the average aquarist can be forgiven for thinking this group of livebearers only consists of a few species, all of which need warm brackish water to survive in captivity and feed on little else but algae. Nothing can be further from the truth!
Myth over reality
These myths about mollies have become so widespread and ingrained in hobby literature that they are now taken as gospel truth by many aquarists. A quick glance at a list of the wild species and where they are found tells you that they come from just about every type of habitat imaginable. Yes they do occur in warm, brackish or even marine conditions, but also in freshwater mountain streams where the ground is often coated with a film of ice on a cold winter’s night.
What this means in reality is that mollies will adapt to most conditions in captivity except poor water quality. They really hate any trace of ammonia or nitrite and will even start shimmying if the nitrate reading starts to rise. Good filtration combined with regular large partial water changes will keep them healthy without the need of the addition of salt.
The only time some modification to the water chemistry may be needed will be in those areas where the pH is acidic and even here it will depend on which species are being kept. Most of the cultivated forms are bred in neutral to alkaline conditions and often in slightly brackish water. These fish find it difficult to adapt to soft acidic water and do much better if the water is hardened a little and the pH raised so it is moderately alkaline.
Apart from water quality the other great “Molly myth” is that these fish are algae eating vegetarians. This is simply not true. Yes they will eat algae but what the mollies are actually feeding on are aufwuchs which live on the algae. When this is taken into account we see the whole dietary needs of mollies have been misjudged. This was vividly brought home to me when I was watching a pair of large cichlids looking after a brood of babies. They were surrounded on all sides by a school of Mollies which circled them like a pack of wolves. Every so often they would test the cichlids’ defences and try to dart in and grab a few fry. The adults chased them off time and again but while they saw two off, a third one would dive in and secure a tasty meal. Not quite the behaviour of an algae eating vegetarian!
So what is the correct diet for Mollies? A good quality commercial fish food combined with regular feeds of live (or frozen alternative) foods. Don,t waste yours or your mollies’ time with lettuce or other vegetable matter but do try to have a healthy growth of plants in the aquarium. These host huge numbers of aufwuchs and will provide a vital supplement to their diet. Broad leafed Amazon swords work best for this since they have a large leaf area for the mollies to graze on and are tough enough to stand up to the rough treatment.
Armed with the knowledge of the correct diet and conditions your mollies need to thrive, they will soon develop into magnificent mollies.
Cultivated colour forms
Most cultivated mollies have their origins in two different species of Sailfin molly (Poecilia latipinna and Poecilia velifera) and a multitude of short fin mollies. Originally it was just Poecilia mexicana and Poecilia sphenops which were crossed in to create different colour forms, but over the last 20 years or so breeders have had access to many more wild forms of molly. We know the origin of the gene which bright orange mollies have, thanks to Dr Joanne Norton passing the information on. This gene naturally occurs in a population of Cave Mollies from southern Mexico. When crossed into an Albino Sailfin molly it produced a peach coloured fish. Other crosses with different strains of cultivated molly produced bright orange fish.
Cultivated fin forms
Looking at the dorsal fin of a Sailfin molly you might be tempted to think this was not a natural fish but a man-made variety. In fact wild fish with huge dorsal fins do occur but not every male in a wild population has the same sized dorsal fin. At least four size morphs of Poecilia latipinna have been isolated and these range in size from 2” fish with very small dorsal fins up to 4” beauties with huge sail-like dorsal fins. It was these very large fish which were used to father the cultivated varieties we see today.
A few man-made fin varieties have cropped up over the years. Lyretail is the commonest in the trade. A fish having this gene has the top and bottom lobe of its tail elongated into a lyre shaped fin. This gene rarely affects the other fins so it is possible for male lyretail mollies to fertilise female lyretails and produce a true breeding strain for this characteristic.
A veiltail sport has also occurred in which all the fins, but primarily the tail, are elongated. This is still a rarity in the trade and would need a normal finned male to mate with.
Cultivated body forms
Call them what you will but Balloon mollies seem to be with us to stay. Why any breeder would want to work with such a deformed animal is beyond me, but several commercial fish farms do breed huge quantities of these creatures and people buy them once they reach aquarium shops.
For those people that do want to breed Balloon mollies both sexes are fully functional and strains will breed true. The gene is recessive so if you cross them with a normal strain you will end up with 100% normal looking babies. Next generation, however, the Balloon gene will pop out again with about 25% of the babies being Balloon mollies.