Why the tank must be mature before shrimp arrive
Cherry shrimp eat biofilm - the microscopic layer of algae and microorganisms that coats every surface of an established aquarium - more than they eat anything you add. A brand-new tank, however clean its test readings, is a desert to a shrimp. So the first rule of a cherry shrimp setup is sequencing: plant the tank, cycle it, then let it run for several more weeks with light on and a pinch of fish food now and then, until the glass, wood and leaves carry that slight slippery film. Only then add shrimp. This waiting is the whole difference between a colony that breeds and a group that dwindles.
A small planted tank with a shrimp-safe filter
Five to 10 gallons suits a starter colony well. Filtration must be gentle and, above all, shrimplet-proof: a sponge filter run on an air pump is the standard choice, because newborn cherry shrimp are the size of a comma and any exposed intake will swallow a generation. If you use a powered filter, cover its intake with fine foam. Plant generously - java moss is the classic, giving babies hiding and grazing in one tangle - and add a piece of driftwood or a few stones as extra biofilm surface. Dark substrate makes the red colour glow, and an inert substrate is safer than an active one for a beginner, since it does not fight your water chemistry.
Stability beats perfect numbers
Tank-bred cherry shrimp are adaptable: they handle a broad band of temperatures in the high 60s to low 80s and near-neutral water, and fancy precision matters far less than steadiness. What kills them is change - a big cold water change, a sudden swing in mineral content, a tank stripped bare by over-cleaning. Keep water changes small, around 10 to 20 percent weekly, matched for temperature and dripped or poured in slowly. Two hard rules stand above the rest: never let copper near the tank, since copper-based fish treatments and some plant fertilisers are lethal to shrimp, and never rinse the sponge filter in tap water - squeeze it in removed tank water so the colony's biofilm engine survives.
Starting the colony and feeding it
Buy ten or more shrimp to start, from a local breeder if possible, because shrimp raised in water like yours settle in far better than shipped imports. You want both sexes - females are larger, deeper red, and show a yellowish saddle of eggs behind the head - and in a settled tank, berried females carrying eggs under the tail appear within months. Feed lightly: the biofilm does most of the work, so a small piece of blanched vegetable, a shrimp pellet or a leaf such as a dried Indian almond leaf once or twice a week is plenty. Uneaten food is the main way beginners pollute a shrimp tank.
Tankmates, honestly assessed
Almost every fish eats baby cherry shrimp, and many eat adults. A shrimp-only tank, perhaps with a snail or two, is the setup that produces the hundreds-strong colony people picture. If fish must share, choose tiny, peaceful species, plant very densely, and accept that the colony will grow slowly and hide more. Otocinclus are the usual safest companions. Decide before you buy which you actually want - a shrimp colony with a few fish, or a fish tank with a few surviving shrimp - because the tank design follows that answer.
Because cherry shrimp forgive ordinary water but punish swinging water, the keeper's best tool is a record: log each test result and water change against the tank in KinsLe's Pet Passport, and a slow drift in the numbers shows up on the page weeks before it shows up in the colony.