Cichlids are a diverse group of fishes. Primarily differentiated by region of origin, there are hundreds of cichlid species available for hobbyists to keep and culture. Before you decide to bring some cichlids home to add to your aquarium, it is vital to research their optimum water quality parameters, space requirements, environmental design, stocking densities, breeding practices, feeding behavior and diet. There is no "one rule" for all cichlid species!
Water Quality Parameters
Since cichlids come from so many varied regions, there are restrictions against mixing species based on varying water quality needs. Depending on your species and their native region, you may require soft, acidic water or more basic, hard water. Many cichlid owners start with RO or reverse osmosis water, since it gives them the ability to manipulate their source water, especially for acidic, soft water aquariums suitable for South American cichlid species. For most African cichlid species, hard, basic water is needed, and special salt mixes for these species are available at fish stores and can be added to the RO water to mix it to the appropriate pH, hardness (GH) and alkalinity (KH),
Cichlids come in a wide variety of sizes, but don't think that smaller fish need less room! Some species of cichlids can be very aggressive over resources such as territory, hiding places, breeding space, mates and food. Many cichlid owners should consider a larger tank than necessary when mixing multiple species. For species with strict stocking densities, do your research first. If it is your first time with cichlids, stick to easy-going, less aggressive species, such as some of the Central American cichlids. African cichlids are very territorial and will chase each other around the aquarium, so a large tank with many hiding spaces is needed for them.
When designing your aquarium, it's easy to consider what you find appealing, not what your fish need. Try to consider your intended species' entire life cycle. What type of environment most closely resembles their natural environment? If you intended to breed your fish, what reproductive strategy do your fish use? If you plan to use "natural elements," such as found rocks or wood pieces, make sure the type of rock and species of wood is safe for fish and properly cleaned prior to adding to your tank.
Many owners make the mistake of over-decorating their aquariums. Larger fish, fish that swim in schools, flighty or aggressive fish are easily snagged on decor items such as branches or twigs. If your fish need cover, but don't do well with solid objects, consider switching rocks and wood for fake or live plants.
Some aggressive fish may take personal offense to some elements in their tank and attack them. This could be a misplaced plant, a humming aerator or an electronic heater. Necessary elements, such as heaters, may require the addition of a sump to keep your fish from hurting themselves and destroying equipment. If you do not have the option of adding a sump, you may need to fortify your equipment with a false back or secret cave your fish cannot access.
The type of decor in the aquarium will vary widely from African cichlids, which require large rock formations with many caves and niches, to heavily planted aquariums for angelfish and other Amazon species.
There are a few species of cichlids with very strict stocking densities. Too many fish and they fight. Too few fish and they fight. Trying to balance your population may seem like a losing battle at times. Many cichlid resources leave out this critical information when you are getting ready to purchase fish. It is best to contact your local cichlid breeder or your local cichlid club to make sure your species are stocked at the correct density. Since there are so many different species of cichlids out there, an expert in your species may not be local. A good book on cichlids, such as The Most Complete Colored Lexicon of Cichlids, will help you determine how many fish of each species you can keep in an aquarium. A general rule is that cichlids require twice as much room per inch of body length than most other aquarium fish (That is, they need over 2 gallons of water per inch of adult body length).
There are many different breeding strategies employed by the various cichlid species. Some are mouth brooders, where the parent fish carries the eggs in its mouth; some will build elaborate caves and lay their eggs on the side walls, carefully guarding them; Some lay their eggs on the leaves of aquatic plants; others are open water spawners, throwing their eggs and sperm about the tank. If you plan on breeding your fish, be sure you have a male and female and their ideal breeding setup. If you are NOT planning on breeding your fish, try to keep single-sex tanks or be prepared for potentially aggressive, unfulfilled spawning desires. Just because you didn't consider breeding more fish, doesn't mean your fish won't.
Depending on where they live in the wild, various species of cichlids will have different feeding strategies. Some eat at the surface, some in the middle of the water column, and some on the bottom, digging through substrate. A few species are predators that will eat other fish, or nibble on their scales, fins and even eyes. Although many captive-bred cichlid species have learned how to swim up to the top of the tank at feeding time, you will need to consider how your fish find their food. If you have a lot of surface feeders and only a few bottom feeders, how will the fish on the bottom get enough to eat? Do you have any species that are especially aggressive toward food and will bully anyone who looks at them while they try to eat? Do you have appropriate substrate for bottom feeding fish to dig through? Does your species of cichlid prefer live food (such as Oscars) or frozen food? There are many important points to consider when feeding your fish and simply "dumping some food at the top" will not work for every system and species.
Along with the wide variety of cichlid species comes a diverse collection of herbivores, omnivores, carnivores and all levels in between. Depending on what mix of species you choose, you may need more than one diet to keep all your fish healthy. Do not assume a can of "cichlid flakes" will do the job. Many cichlid species do best with a varied diet.
There is no "one size fits all" when it comes to a cichlid aquarium. Do thorough research before you buy anything! Although you may have your heart set on one species, you may not have the space or setup to house them. Don't cut corners thinking your new cichlids will make do with whatever you have ready. Many of these species have strict water quality, space, diet and other requirements that will cause serious disease and possibly death if you ignore them. Cichlids are also long-lived species of fish, often living from 10 to even 20 years in aquariums! So, be sure to plan ahead and get the correct setup - as they will be your pets for a long time if well cared for.