A kribensis looks like a modest community fish in the shop tank, but its adult size, and the difference between the sexes, decides how much floor space a pair will eventually demand from you.
Males, females, and the size gap
A male kribensis grows to about 4 inches, with longer, more pointed fins and a slimmer, more streamlined body. A female stops nearer 3 inches, yet often looks the more impressive fish: she is deeper-bodied, and when she is in breeding condition her belly flushes a rich wine-red that no male matches. Juveniles in a shop are hard to sex, so buyers who want one pair should expect to start with a small group or take the shop's help, knowing the spare fish will need homes once a pair forms. Growth to full size takes the better part of a year in a well-fed tank, and a stunted, cramped start can leave an adult permanently undersized and washed out.
What adult size means for territory
Four inches sounds harmless, and for a single fish it is. The catch is that adult kribensis are cave-spawning cichlids, and a mature pair treats a cave and the surrounding patch of substrate as theirs. In a small tank that territory can be most of the floor, and other bottom fish will be chased from it whenever eggs or fry are present. Give a pair a tank with real length, at least one enclosed cave per potential territory, and sight breaks made from plants, wood, or rock so a fish being chased can get out of view. Dither fish that swim in open water help a shy pair feel secure, but anything that insists on sharing the cave floor will have a hard time once breeding starts.
Feeding a kribensis up to full size
Kribensis are unfussy omnivores, and reaching a healthy adult size is mostly about variety rather than quantity. A small staple pellet or flake as the base, regular frozen or live foods such as daphnia and bloodworm-style offerings in moderation, and some vegetable matter in the diet will grow a juvenile steadily without fouling the water. Females colour up best when they are well conditioned but not overfed; a permanently bloated fish is not a breeding-ready one. Because adults sift and pick around the substrate, a softer sand or fine gravel lets them forage naturally and keeps their mouths and gill covers in better shape than coarse, sharp gravel does.
Will a full-grown kribensis fit your community?
A lone adult or a pair in a suitably long tank mixes well with mid-water fish too large to be seen as food and too calm to harass the cichlids. Very small fry of other species may be eaten, and long-finned, slow fish can be nipped if they drift into the pair's territory at breeding time. Plan on the adults, not the juveniles you bought: a community that looks balanced at purchase can tilt once the male hits 4 inches and the pair starts defending a cave, so leave headroom in the stocking from the start rather than correcting an overcrowded floor later.
When a bonded pair outgrows a keeper's plans, KinsLe Transferrable Profiles hand the new owner their cave layout, feeding routine, and record of past spawns together with the fish, so the pair's hard-won stability is not lost in the move.