For first time aquarium starters, molly fish are considered the best.
The primary reason is that they have very few needs, so that you can take care of them with ease.
They are well known for their grace and hardy nature.
They often become naughty when they are being kept in an aquarium with other fish.
They have been found to pinch the fins of other fish in the aquarium and cause disturbances within the aquarium.
Other fish due to this reason might get infection due to injuries and, therefore, eventually dies.
Aggressiveness of the fish is evident from their bodies.
They possess very strong jaws accompanied with sharp teeth.
These features help them in eating algae that get accumulated inside the aquarium.
Their digestive system is very strong and can even digest the hardest possible algae without any difficulty.
Not only this, they are also capable of damaging the other aquarium plants.
One more point to be noted is that these fish are not the actual fresh water fish and, therefore, need some amount salt water in the aquarium.
And, to top it up, they like stay in clean and slightly warm water.
So, after knowing all these negative aspect about the molly fish, is it then appropriate to keep them in the aquarium? Well, it is widely accepted that molly fish are generally incompatible with other tropical fish.
Species like tetras and corydoras are not compatible with molly fish.
However, some other species like glassfish and the wrestling halfbeaks live comfortably with the molly.