A quarantine tank succeeds through simplicity and observation, not equipment. Whether the cichlid is new or unwell, the tank has one job: hold water quality steady in a bare, calm space where you can watch him closely for days to weeks. Set it up completely before the fish goes in, and keep everything used in it separate from your main tank.
What goes in, and what stays out
Gather a plain tank of roughly 40 to 75 litres for a single cichlid, a sponge filter already matured in your main tank, a heater with a guard, a thermometer, a tight lid, water conditioner, a smooth pipe section or plain flowerpot as a hide, a dedicated net, a dedicated jug or bucket, and a notebook. The base stays bare: no gravel, no sand, no rock piles. A bare base shows you uneaten food and waste immediately, wipes clean in seconds, and leaves debris nowhere to rot unseen. Borrowed mature filter media matters more than anything else on this list, because it brings working bacteria with it and spares the fish the ammonia spike of a brand-new setup. A lid is essential, since cichlids jump, and a sick fish startles easily.
Match the water to the source tank
Fill the tank with conditioned water and bring it to the same temperature as the tank the cichlid is leaving. Test both tanks and compare readings for temperature, pH and hardness before the move, adjusting gradually if they differ, because a cichlid already under strain tolerates sudden chemistry swings poorly. Run the filter and heater for several hours and confirm the thermometer holds steady. When you transfer him, float or drip-acclimate only if the source water differs noticeably; when the two tanks match, a swift, gentle net transfer through the water surface causes the least stress. Dim the room light for the first hours and let him find the hide.
Run it on observation, not intervention
Quarantine is a watching brief. Feed once a day, sparingly, and remove whatever remains after a few minutes so waste never accumulates. Change about a quarter of the water every day or two with conditioned water matched for temperature, siphoning debris from the bare base as you go. Note the same things at the same time daily: whether he ate and how eagerly, how fast he breathes, whether fins stay clamped or relaxed, how waste looks, and whether he uses the hide or patrols openly. Keep your hands, nets and jugs for this tank separate, and always work on the main tank first and the quarantine tank last, washing hands between them, so nothing travels from the sick fish to healthy stock.
How long, and what ends it
A new cichlid commonly stays in quarantine for several weeks, long enough for hidden problems to declare themselves while he eats and settles. A sick cichlid stays until he has been visibly well, eating strongly and behaving normally, for a clear run of days, and your vet or aquatic specialist agrees the observation period is complete. Never return a fish simply because the tank is needed elsewhere, and never move a fish who still hides constantly, refuses food or breathes rapidly. If signs worsen, if white spots, fungus-like patches, sores or a swollen belly appear, or if he stops eating altogether, contact an aquatic vet promptly with your dated notes rather than guessing at causes or adding anything to the water on speculation.
Break it down without spreading anything
When quarantine ends, keep the tank running empty for a short period if another arrival is expected soon, or strip it down fully. Wash equipment with plain hot water, dry it thoroughly in air, and return the sponge filter to quarantine duty only, not to the main tank, after a sick fish has used it. File the notebook pages with the dates, source shop and readings from this stay, since the next quarantine begins smarter with them. When the next newcomer arrives, the record inside KinsLe turns last season's readings into your starting template, filed under that fish's own Pet Passport.