What sorting rank actually looks like
Young cichlids are supposed to squabble; rank is how they organise a shared space. In a healthy settling pattern the confrontations are brief and ritualised: a flare, a short chase, sometimes a jaw-to-jaw wrestle between near-equals, and then it ends — the loser retreats a short distance and the winner goes back to its own business. Crucially, the consequences are mild. Subordinate fish still come out to feed, still show reasonable colour, and still move around the tank when the dominant fish is elsewhere. The targeting is also democratic: today the argument is between two fish, tomorrow between two others. A hierarchy is a queue, not a campaign.
The bullying pattern, sign by sign
Bullying is the same behaviours with the fairness removed, and one fish pays for all of it. The targeted youngster is chased on sight, not after a boundary dispute, and learns to live in one hiding place or pressed into a top corner. It stops coming out at feeding time, or darts in and flees without eating. Its fins begin to show it — nipped edges, clamped posture, torn tails that never heal — and its colour washes out to a permanent pale while tankmates colour up. That combination, sustained over days rather than hours, is no longer a hierarchy forming. It is one fish being ground down, and left alone it usually ends in sickness or death from stress alone.
Why it tips over at this age
The slide from sorting to bullying usually has a mechanical cause. Growth rates diverge fast in young cichlids, and a fish that was an equal in spring can be a tyrant by summer; males maturing ahead of the group are another common trigger. Space and sightlines matter just as much: in a bare or small tank a subordinate has nowhere the dominant fish cannot see, so every encounter continues until someone is cornered. Too few shelters, a single cave everyone wants, or a group so small that one victim absorbs every dispute will all push normal behaviour over the line. The fish are rarely the problem in isolation; the arithmetic of size, space and hiding places is.
Intervene in order, mildest first
Start by breaking sightlines: add shelters, plants or rockwork so a retreating fish can actually disappear, and rearrange the decor to dissolve the territories both fish are defending. Feed in two or three spots at once so the victim eats without crossing the tank. If the pattern persists — and certainly once fins are torn, a fish has stopped eating, or one is living in a corner — separate them: move the aggressor out for a spell, or grow the victim on in another tank until size evens the contest. Watching the pattern closely — who chased, who hid, who ate — is what makes the call early. For a borderline case, put a follow-up question to KinsLe's Kimmy; she answers using the KinsLe Answers library.