diff --git a/src/__tests__/integration/creator-holders-quantity-sort.test.ts b/src/__tests__/integration/creator-holders-quantity-sort.test.ts
new file mode 100644
index 0000000..97c4bc1
--- /dev/null
+++ b/src/__tests__/integration/creator-holders-quantity-sort.test.ts
@@ -0,0 +1,111 @@
+import supertest from 'supertest';
+import app from '../../app';
+import { prisma } from '../../utils/prisma.utils';
+
+describe('GET /api/v1/creators/:id/holders — quantity descending order (#604)', () => {
+   let creatorId: string;
+   let singleHolderCreatorId: string;
+
+   beforeAll(async () => {
+      const user = await prisma.user.create({
+         data: {
+            id: 'holder-qty-sort-test-user',
+            email: 'holder-qty-sort-test@example.com',
+            passwordHash: 'dummy-hash',
+            firstName: 'HolderQty',
+            lastName: 'SortTest',
+         },
+      });
+
+      const creator = await prisma.creatorProfile.create({
+         data: {
+            userId: user.id,
+            handle: 'holder-qty-sort-creator',
+            displayName: 'Holder Quantity Sort Creator',
+         },
+      });
+      creatorId = creator.id;
+
+      // Seed four holders with quantities 5, 1, 10, 3 for the same creator
+      await prisma.keyOwnership.createMany({
+         data: [
+            { ownerAddress: '0xqty-5', creatorId: creator.id, balance: 5 },
+            { ownerAddress: '0xqty-1', creatorId: creator.id, balance: 1 },
+            { ownerAddress: '0xqty-10', creatorId: creator.id, balance: 10 },
+            { ownerAddress: '0xqty-3', creatorId: creator.id, balance: 3 },
+         ],
+      });
+
+      const singleUser = await prisma.user.create({
+         data: {
+            id: 'holder-qty-sort-single-user',
+            email: 'holder-qty-sort-single@example.com',
+            passwordHash: 'dummy-hash',
+            firstName: 'HolderQtySingle',
+            lastName: 'SortTest',
+         },
+      });
+
+      const singleCreator = await prisma.creatorProfile.create({
+         data: {
+            userId: singleUser.id,
+            handle: 'holder-qty-sort-single-creator',
+            displayName: 'Holder Quantity Sort Single Creator',
+         },
+      });
+      singleHolderCreatorId = singleCreator.id;
+
+      await prisma.keyOwnership.create({
+         data: {
+            ownerAddress: '0xqty-single',
+            creatorId: singleCreator.id,
+            balance: 7,
+         },
+      });
+   });
+
+   afterAll(async () => {
+      await prisma.keyOwnership.deleteMany({
+         where: { creatorId: { in: [creatorId, singleHolderCreatorId] } },
+      });
+      await prisma.creatorProfile.deleteMany({
+         where: { id: { in: [creatorId, singleHolderCreatorId] } },
+      });
+      await prisma.user.deleteMany({
+         where: {
+            id: {
+               in: ['holder-qty-sort-test-user', 'holder-qty-sort-single-user'],
+            },
+         },
+      });
+      await prisma.$disconnect();
+   });
+
+   it('returns all four holders sorted by quantity descending: 10, 5, 3, 1', async () => {
+      const res = await supertest(app).get(
+         `/api/v1/creators/${creatorId}/holders`
+      );
+      expect(res.status).toBe(200);
+
+      const items = res.body.data.items;
+      expect(items).toHaveLength(4);
+
+      const quantities = items.map((item: any) => item.key_balance);
+      expect(quantities).toEqual([10, 5, 3, 1]);
+
+      const addresses = items.map((item: any) => item.wallet_address);
+      expect(addresses).toEqual(['0xqty-10', '0xqty-5', '0xqty-3', '0xqty-1']);
+   });
+
+   it('handles a creator with a single holder correctly', async () => {
+      const res = await supertest(app).get(
+         `/api/v1/creators/${singleHolderCreatorId}/holders`
+      );
+      expect(res.status).toBe(200);
+
+      const items = res.body.data.items;
+      expect(items).toHaveLength(1);
+      expect(items[0].wallet_address).toBe('0xqty-single');
+      expect(items[0].key_balance).toBe(7);
+   });
+});
diff --git a/src/config.schema.ts b/src/config.schema.ts
index 24ff999..a7307db 100644
--- a/src/config.schema.ts
+++ b/src/config.schema.ts
@@ -97,7 +97,7 @@ export const envSchema = z
          .int()
          .positive()
          .default(300000),
-      SLOW_QUERY_THRESHOLD_MS: z.coerce.number().int().positive().default(500),
+      SLOW_QUERY_THRESHOLD_MS: z.coerce.number().int().positive().default(200),
       DB_POOL_WAIT_WARN_MS: z.coerce.number().int().positive().default(500),
       DB_POOL_WAIT_ERROR_MS: z.coerce.number().int().positive().default(2000),
       CREATOR_LIST_SLOW_QUERY_THRESHOLD_MS: z.coerce
diff --git a/src/modules/creators/creator-detail-price-change-sign.integration.test.ts b/src/modules/creators/creator-detail-price-change-sign.integration.test.ts
new file mode 100644
index 0000000..0c78e16
--- /dev/null
+++ b/src/modules/creators/creator-detail-price-change-sign.integration.test.ts
@@ -0,0 +1,114 @@
+import supertest from 'supertest';
+import app from '../../app';
+import { prisma } from '../../utils/prisma.utils';
+
+const USER_ID_UP = 'creator-price-change-sign-up-user';
+const HANDLE_UP = 'creator-price-change-sign-up';
+
+const USER_ID_DOWN = 'creator-price-change-sign-down-user';
+const HANDLE_DOWN = 'creator-price-change-sign-down';
+
+describe('creator detail endpoint — priceChange24h sign (#576)', () => {
+   let creatorIdUp: string;
+   let creatorIdDown: string;
+
+   beforeAll(async () => {
+      await prisma.user.upsert({
+         where: { id: USER_ID_UP },
+         create: {
+            id: USER_ID_UP,
+            email: 'creator-price-change-sign-up@example.test',
+            passwordHash: 'dummy-hash',
+            firstName: 'Price',
+            lastName: 'Up',
+         },
+         update: {},
+      });
+      await prisma.user.upsert({
+         where: { id: USER_ID_DOWN },
+         create: {
+            id: USER_ID_DOWN,
+            email: 'creator-price-change-sign-down@example.test',
+            passwordHash: 'dummy-hash',
+            firstName: 'Price',
+            lastName: 'Down',
+         },
+         update: {},
+      });
+
+      const creatorUp = await prisma.creatorProfile.upsert({
+         where: { userId: USER_ID_UP },
+         create: {
+            userId: USER_ID_UP,
+            handle: HANDLE_UP,
+            displayName: 'Price Change Sign Up Creator',
+         },
+         update: {},
+      });
+      creatorIdUp = creatorUp.id;
+
+      const creatorDown = await prisma.creatorProfile.upsert({
+         where: { userId: USER_ID_DOWN },
+         create: {
+            userId: USER_ID_DOWN,
+            handle: HANDLE_DOWN,
+            displayName: 'Price Change Sign Down Creator',
+         },
+         update: {},
+      });
+      creatorIdDown = creatorDown.id;
+
+      // Current price higher than the 24h-ago snapshot -> positive change
+      await prisma.creatorPriceSnapshot.create({
+         data: {
+            creatorId: creatorIdUp,
+            currentPrice: BigInt(1_500_000),
+            price24hAgo: BigInt(1_000_000),
+            lastTradeAt: new Date(),
+         },
+      });
+
+      // Current price lower than the 24h-ago snapshot -> negative change
+      await prisma.creatorPriceSnapshot.create({
+         data: {
+            creatorId: creatorIdDown,
+            currentPrice: BigInt(800_000),
+            price24hAgo: BigInt(1_000_000),
+            lastTradeAt: new Date(),
+         },
+      });
+   });
+
+   afterAll(async () => {
+      await prisma.creatorPriceSnapshot.deleteMany({
+         where: { creatorId: { in: [creatorIdUp, creatorIdDown] } },
+      });
+      await prisma.creatorProfile.deleteMany({
+         where: { handle: { in: [HANDLE_UP, HANDLE_DOWN] } },
+      });
+      await prisma.user.deleteMany({
+         where: { id: { in: [USER_ID_UP, USER_ID_DOWN] } },
+      });
+      await prisma.$disconnect();
+   });
+
+   it('returns a positive priceChange24h when the price increased over 24h', async () => {
+      const res = await supertest(app).get(
+         `/api/v1/creators/${creatorIdUp}/profile`
+      );
+      expect(res.status).toBe(200);
+      expect(res.body.data).toHaveProperty('priceChange24h');
+      expect(res.body.data.priceChange24h).not.toBeNull();
+      expect(res.body.data.priceChange24h).toBeGreaterThan(0);
+   });
+
+   it('returns a negative priceChange24h when the price decreased over 24h', async () => {
+      const res = await supertest(app).get(
+         `/api/v1/creators/${creatorIdDown}/profile`
+      );
+      expect(res.status).toBe(200);
+      expect(res.body.data).toHaveProperty('priceChange24h');
+      expect(res.body.data.priceChange24h).not.toBeNull();
+      expect(res.body.data.priceChange24h).toBeLessThan(0);
+   });
+});
diff --git a/src/utils/prisma.utils.ts b/src/utils/prisma.utils.ts
index 1e7eec9..7603eef 100644
--- a/src/utils/prisma.utils.ts
+++ b/src/utils/prisma.utils.ts
@@ -33,6 +33,17 @@ function normalizeArgsForFingerprint(value: unknown, depth = 0): unknown {
    return '?';
 }
 
+/** Maps a Prisma client operation to the SQL verb it maps to, for logging. */
+function mapOperationToSqlVerb(
+   operation: string
+): 'select' | 'insert' | 'update' | 'delete' | string {
+   if (/^(find|count|aggregate|groupBy)/.test(operation)) return 'select';
+   if (/^create/.test(operation)) return 'insert';
+   if (/^(update|upsert)/.test(operation)) return 'update';
+   if (/^delete/.test(operation)) return 'delete';
+   return operation;
+}
+
 /**
  * Build a short deterministic hash that identifies the query pattern (model,
  * operation, and arg structure) without including any parameter values.
@@ -147,8 +158,11 @@ export const prisma = basePrisma.$extends({
                   logger.warn(
                      {
                         type: 'slow_query',
+                        query_name: `${model ?? 'unknown'}.${operation}`,
+                        table: model,
+                        operation: mapOperationToSqlVerb(operation),
+                        duration_ms: elapsedMs,
                         model,
-                        operation,
                         fingerprint: buildQueryFingerprint(
                            model,
                            operation,