diff --git a/ApiCore-Backend/src/colonies/colonies.service.spec.ts b/ApiCore-Backend/src/colonies/colonies.service.spec.ts
index 14eeeb4..f301d4d 100644
--- a/ApiCore-Backend/src/colonies/colonies.service.spec.ts
+++ b/ApiCore-Backend/src/colonies/colonies.service.spec.ts
@@ -1,4 +1,4 @@
-import { NotFoundException } from '@nestjs/common';
+import { ConflictException, NotFoundException } from '@nestjs/common';
 import { ColoniesService } from './colonies.service';
 import { PrismaService } from '../prisma/prisma.service';
 import { AuditLogService } from '../audit/audit-log.service';
@@ -143,6 +143,16 @@ describe('ColoniesService', () => {
     expect(lineageArg.data.toColonyId).toBe('colony-1');
   });
 
+  it('move rejects a non-active colony', async () => {
+    prisma.colony.findUnique.mockResolvedValue({
+      ...parentColony,
+      status: 'DISSOLVED',
+    });
+    await expect(
+      service.move('colony-1', { apiaryId: 'apiary-2' }, 'user-1'),
+    ).rejects.toBeInstanceOf(ConflictException);
+  });
+
   it('dissolve sets status DISSOLVED and records DEACTIVATE', async () => {
     prisma.colony.findUnique.mockResolvedValue(parentColony);
     prisma.colony.update.mockResolvedValue({
diff --git a/ApiCore-Backend/src/colonies/colonies.service.ts b/ApiCore-Backend/src/colonies/colonies.service.ts
index 272b044..60ffcbf 100644
--- a/ApiCore-Backend/src/colonies/colonies.service.ts
+++ b/ApiCore-Backend/src/colonies/colonies.service.ts
@@ -1,4 +1,8 @@
-import { Injectable, NotFoundException } from '@nestjs/common';
+import {
+  ConflictException,
+  Injectable,
+  NotFoundException,
+} from '@nestjs/common';
 import { PrismaService } from '../prisma/prisma.service';
 import { AuditLogService } from '../audit/audit-log.service';
 import { Colony } from '../../generated/prisma';
@@ -27,6 +31,14 @@ export class ColoniesService {
     return colony;
   }
 
+  private assertActive(colony: Colony): void {
+    if (colony.status !== 'ACTIVE') {
+      throw new ConflictException(
+        `Colony ${colony.id} is not active (status: ${colony.status})`,
+      );
+    }
+  }
+
   async create(dto: CreateColonyDto, actingUserId: string): Promise<Colony> {
     const colony = await this.prisma.colony.create({ data: { ...dto } });
     await this.auditLog.record({
@@ -66,6 +78,7 @@ export class ColoniesService {
     actingUserId: string,
   ): Promise<Colony> {
     const before = await this.findById(id);
+    this.assertActive(before);
     const colony = await this.prisma.$transaction(async (tx) => {
       const updated = await tx.colony.update({
         where: { id },
@@ -98,6 +111,7 @@ export class ColoniesService {
     actingUserId: string,
   ): Promise<Colony> {
     const parent = await this.findById(id);
+    this.assertActive(parent);
     const child = await this.prisma.$transaction(async (tx) => {
       const created = await tx.colony.create({
         data: {
@@ -134,6 +148,7 @@ export class ColoniesService {
     actingUserId: string,
   ): Promise<Colony> {
     const survivor = await this.findById(id);
+    this.assertActive(survivor);
     await this.prisma.$transaction(async (tx) => {
       for (const mergedColonyId of dto.mergedColonyIds) {
         const merged = await tx.colony.findUnique({
@@ -142,6 +157,7 @@ export class ColoniesService {
         if (!merged) {
           throw new NotFoundException(`Colony ${mergedColonyId} not found`);
         }
+        this.assertActive(merged);
         await tx.colony.update({
           where: { id: mergedColonyId },
           data: { status: 'MERGED', deactivatedAt: new Date() },
diff --git a/ApiCore-Backend/test/colonies.e2e-spec.ts b/ApiCore-Backend/test/colonies.e2e-spec.ts
index acad51b..d4beda6 100644
--- a/ApiCore-Backend/test/colonies.e2e-spec.ts
+++ b/ApiCore-Backend/test/colonies.e2e-spec.ts
@@ -188,5 +188,11 @@ describe('Colonies (e2e)', () => {
       .get(`/api/v1/colonies/${colonyId}`)
       .set('Authorization', `Bearer ${staffToken}`)
       .expect(200);
+
+    await request(app.getHttpServer())
+      .post(`/api/v1/colonies/${colonyId}/move`)
+      .set('Authorization', `Bearer ${beekeeperToken}`)
+      .send({ apiaryId: apiaryAId })
+      .expect(409);
   });
 });