Summarize this article in one sentence.
Parrot cichlids can grow as large as 10 inches (25 cm) long. For this reason, you'll need to buy at least a 42-gallon (159 L) tank if you want to keep only one fish. Aim for 10 additional gallons (38 L) for each fish if you're planning on giving your fish some companions. Parrot cichlids like to have several hiding places along the bottom of the aquarium, so a taller tank wouldn't help. Parrot cichlids are large fish with healthy appetites. Their tendency to dig in the substrate can stir up dirt and algae. This is why they require a larger filter. A heavy-duty wet/dry filter will help to remove these waste products and keep the water clean. Purchase a filter that can be mounted to the back of the tank. Avoid anything that goes under the substrate, as digging fish can easily disturb its functioning. Many breeds of parrot cichlids originate in warm South American climates. Keep the aquarium temperature about 76 to 84 °F (24 to 29 °C). Even blood parrot cichlids, bred in captivity by humans, thrive in warmer waters. Temperatures below 80 °F (27 °C) might cause cichlids to become less social. Parrot cichlids like to dig, so make sure the substrate is soft. Opt for fine dark sand, which they can comfortably burrow under. Avoid putting plants in the aquarium, since the cichlid's tendency to dig could knock them over. Parrot cichlids can be territorial, especially if you plan on adding smaller tankmates. Keep broken flowerpots, small rocks, driftwood, or stacked rocks to form caves that provide the fish with hiding spots.

Summary:
Purchase a large aquarium. Install a large canister filter. Keep a heater in the aquarium. Add the substrate. Provide the fish with hiding places.