When it comes to any fish species, bigger is always better but for the home aquarium, it’s not always possible to have a massive tank! Cichlids are no exception since they get much larger then most standard community fish species.
Since cichlids do get large, the smallest tank that is recommend is 29 gallons. The preferred size is 50 gallons. More ground space is better then a tall aquarium size cichlids are all bottom dwellers, they don’t live near the surface otherwise birds would eat them so they’ve adapted to love at the bottom. Also it makes it easier for them to hunt when schools of fish swim above.
If you are going to get African cichlids, you will need to put some rocks and rocky like ornaments in your tank so this is another reason that the fish tank size should larger so that you can have the decorations they require to feel at home and more comfortable and still have enough space for them to swim and grow.
The temperature requirements are not very strict, cichlids are very hardy fish and can tolerate different temperatures but fluctuations are not good for any fish as it creates stress on the fish which can cause illness. Get a good heater and maintain the temperature range between 75 and 80 degrees. A glass heather is not usually recommended especially for the larger tanks because when the fish get very big, they can be strong enough to break the glass on a glass heater is they should be rearranging their rocks, which sometimes can happen. The South American cichlids are very famous for moving around their ornaments and a large Oscar fish can easily crack a heater. The metal heaters are most recommended.
Since you will be packing your aquarium full of fish, a very good filter is not just recommended but it’s absolutely essential. The hang on the back of the tank style filters are not good enough for an aquarium stocked full of cichlids. Sure it’s nice to be able to cram lots of fish in there and ignore the "one inch of fish per gallon" rule with cichlids, but you’ll need to have adequate filtration to make sure that you don’t have ammonia problems which can occur very easily due to poor filtration and all your fish can easily die. A canister filter is highly recommended for cichlids, even if you have a smaller 29 gallon, you should still get a canister filter.
These fish are not very picky about lighting since most of them live at the bottom of a lake or in a muddy river. It’s up to you how often to keep the lights on in the aquarium, however a regular schedule is best for the well being the fish so if you are going to turn the lights on, keep them on for the same amount of time each day. Just like humans, fish benefit from a regular cycle. The more that your lights are left on, the more algae you will have in your tank. If you have a plecostomus, you should leave the lights on at least 8 hours a day to spur algae growth so that the plecostomus does not starve.
The bottom substrate you choose can vary on your personal choice. The most recommended is larger rocks, like pebbles. This is more natural to most species and it enables the tank to be cleaned easier because the siphon will easily be able to pick up the fish feces. Make a very thin layer so that the feces does not fall to the bottom where the siphon tube cannot reach.
Tiny gravel is not recommended because the fish will get large enough to swallow it which can cause problems and maybe even death but this is usually a very common substrate choice. The chance of the fish swallowing the gravel is every slim because they usually spit it out, but the risk is there. Sand and gravel mixed is also a common choice as it simulates the natural river bottom, but it is messy. The easiest and safest choice is larger pebbles.
Water PH is not really a concern, the reason is that most cichlid species are captive bred and they are used to the PH of the water in your city or town. Wild caught specimens may need a different PH depending on where they originate from. If your purchase captive bred cichlids then you don;t need tom concern yourself with PH level. For your information, the ideal PH level for a cichlid aquarium is 6.5 to 7.5
Water hardness is important, they thrive best in hard water. If your city has soft water, you can supplement your aquarium with aragonite
which is old coal pieces ground up. There may be other similar substitutes but consult your local fish vendor to find the best solutions for your particular town, as every city has different water hardness and it’s difficult to say a particular treatment.
Since all the waters in nature where cichlids come from are slightly salted, it is best to add aquarium salt to your water. This also helps to prevent against disease and reduces the stress on the fish. Any commercial aquarium salt from a pet store will do. Salt never evaporates from the water so you will only need to add it when doing a water change. Read the salt requirements for tropical fish as listed on the salt container and use the amount that they suggest.
Water changes will need to be done biweekly. This is the optimal water change frequency although is you have a completely cycled tank and an established canister filter you may be able to get away with 1 change every month. The best way to indicate how often to change your water is to purchase an ammonia and nitrate test kit. If you do a water change every 2 weeks, you won’t need to purchase the test kit because you’ll be fine. Change approximately 15% of the water by using a siphon to pick up all the feces at the bottom of the aquarium. Make sure to add water conditioner to remove the chlorine from the water and be sure to add salt when you add water as well. Cichlids can be jumpers, like most other tropical fish species the aquarium needs to be covered.