Does a Molly Fish Need an Aerator?

Aerator

• Most fish need some oxygen in their water. You can supply this with several different types of aerators and aeration. Water movement at the surface improves the exchange of gases, and increases the amount of oxygen in aquarium water, making water pumps and powerheads ideal aerators. Bubblers, usually comprised of an air pump connected to a porous stone called an airstone, also provide aeration by creating tiny bubbles. Oddly, the bubbles themselves provide negligible oxygenation, but the water movement and turbulence they create at the surface improves water oxygenation. Keep in mind that mollies need more than an aerator to survive, and that most aquarium filters provide enough water movement for oxygenation.

Filter Basics

• Any aquarium with mollies needs real filtration beyond aeration. A dizzying variety of aquarium filters line the shelves of pet shops, but any design that provides mechanical, chemical and biological filtration will work. In mechanical filtration, a filter physically strains debris out of the water. Chemical filtration uses chemicals, like activated carbon or zeolite, to remove contaminants from the water by chemical means. Biological filtration is the most important form of long-term filtration in aquariums. In biological filtration, beneficial bacteria colonize surfaces in an aquarium, and proceed to break down fish waste. While any surface in an aquarium can host these bacteria, many filters feature filter media with a large surface-to-volume ratio to encourage their growth.

Types of Filters

• Powerbox and canister filters both make excellent choices, but both have pros and cons. Powerbox or hanging filters are powered filters than hang on the back of your aquarium. They use a water pump to pull water from the tank into the filter. Within the filter, various types of filter pads perform the three types of filtration. Canister filters are usually canister- or box-shaped. While powerbox filters hang on the back of the aquarium, most canister filters connected to the aquarium via tubes, making it easier to keep the filter out of sight. Canister filters have various media inside them, providing the three types of filtration. Canister filters are usually more expensive, but also usually provide more powerful filtration.

Heaters

• Mollies also require a heater to survive in an aquarium. In fact, mollies come from water on the hotter end of the tropical range. They can survive in temperatures down to 72 degrees Fahrenheit, but need warmer water, typically about 77 to 82 degrees Fahrenheit, to really thrive. You will need some form of aquarium heater in addition to your filter in order to keep mollies healthy and happy.

Salt

• Mollies also need salt in their water to look their best. They may survive without salt, but again, to see them at their best, you should add salt to their water. Do not use table salt. Instead, use rock, kosher or aquarium salt. Dose the water with about 1 teaspoon of salt per gallon of aquarium water. You should also make sure that the other fish in the tank can tolerate this. While this level of salt is nowhere near the salinity of ocean water, it is high enough to kill some fish. Also keep in mind that salt doesn't evaporate when water does; the salinity of your tank will go down only when you do water changes.