🐠 Pro Playbook: Introducing New Fish to Your Aquarium
🧭 Before You Buy: Compatibility & Prep
- 📋 Stocking/behavior check: Confirm size, temperament, territory, and bioload match. Avoid mixing fin-nippers with long-finned fish; keep schooling fish in proper group sizes.
- ⚖️ Water parameters match: Know your tank’s pH/KH/GH/TDS/temp and pick species that thrive in that range.
- 🧪 Seed a quarantine filter: Keep a cycled sponge filter bubbling in your main tank so it’s ready for a QT.
- 🧰 Have meds on hand (fish “medicine cabinet”):
- ❄️ Ich treatment (e.g., malachite green/copper/formalin per label)
- 🦠 Broad-spectrum antibiotics (kanamycin/erythromycin/furan-based)
- 🪱 Anti-parasite (praziquantel, metronidazole; fluke remedies)
- 🧂 Aquarium salt (if species tolerate)
- 🧴 Water conditioner that detoxifies chlorine/chloramine (and optionally binds ammonia)
Don’t wait until you see symptoms—shipping times can cost lives.
🪣 Step 1: Set Up a Proper Quarantine (QT)
- 🏠 Tank: 10–20 gal (or larger for big fish), bare-bottom for easy cleanup.
- 🔥 Heater + 🌬️ sponge filter + 💨 airstone for strong oxygenation.
- 🌿 Hides: PVC elbows, caves, floating plants for cover.
- 🧴 Dedicated tools: Separate nets, siphon, bucket (🔒 biosecurity).
- ⏳ Duration: 2–4 weeks (wild-caught or sensitive species: 4–6 weeks).
📦 Step 2: Arrival Triage (Local vs. Shipped)
- 👜 Local pickup: Usually low ammonia—standard acclimation applies.
- 📦 Shipped fish: Bag water often has high CO₂/low pH (ammonia mostly in safer NH4⁺ form).
- ⚠️ When you open the bag, pH rises → unionized NH₃ spikes and becomes more toxic.
- ✅ Strategy: Keep the bag sealed while floating to match temperature, then choose the right acclimation (below).
🌡️ Step 3: Temperature Acclimation
- 🛟 Float sealed bag in QT 15–20 min to equalize temperature.
- 🧴 If you must open for a long acclimation, add conditioner that binds ammonia to the bag water or the acclimation bucket.
💧 Step 4: Match Water Chemistry (Choose the Right Method)
🥤 Cup Method (good for hardy, store-bought fish)
- Every 5 min, add a small cup of QT water to the bag for 20–30 min.
- 🕸️ Net the fish into QT (🚫 don’t pour bag water in).
💦 Drip Acclimation (best for shrimp, wild-caught, delicate fish)
- Put fish + bag water in a bucket; start a siphon drip (2–4 drips/sec) from QT.
- 45–60 min total. Net fish into QT.
🪂 Plop-and-Drop (for shipped fish with likely high ammonia)
- After floating sealed bag to temp, net fish directly into QT with pre-matched parameters.
- 🚫 Do not prolong contact with bag water; don’t add bag water to tank.
General rules: never add store/shipping water to your tank; always net fish in.
🔦 Step 5: Gentle Introduction
- 🔅 Lights off (or very dim) for the first few hours.
- 🪵 Provide line-of-sight breaks (wood, plants, rock) to reduce stress.
- 🍽️ No feeding for 6–12 hours; offer a small first meal after they settle.
🧪 Step 6: The First 72 Hours (Critical Window)
- 📈 Test daily: Ammonia, nitrite, nitrate, pH, temperature.
- 💨 Maintain strong aeration (new arrivals have higher O₂ demand).
- 🧽 Small, frequent water changes if readings creep up.
- 👀 Observe: breathing rate, appetite, flashing, spots, frayed fins, mucus.
💊 Step 7: Proactive Health Protocol (Optional but Common in QT)
Follow product labels; some species (loaches, Corys, plecos, shrimp) are salt/copper sensitive.
- 🪱 Deworming (praziquantel) once eating well; often a repeat dose 1–2 weeks later.
- 🦠 External parasite coverage if flashing or excess mucus.
- 🧪 Bacterial support only if symptoms appear (fin rot, ulcers, rapid columnaris signs).
- 🧂 Salt can aid osmoregulation for many fish—avoid with scaleless fish/shrimp unless product says safe.
🐟 Step 8: Transition from QT → Display Tank
- ✅ Symptom-free for the full QT period.
- 🍽️ Eating well, normal behavior, stable water readings.
- ♻️ Parameter match (pH/KH/GH/TDS/temp within safe deltas) before transfer.
- 🔁 Repeat a brief temp/chemistry acclimation; move fish with a net.
🪓 Managing Aggression When Adding to the Display
- 🧩 Re-scape right before introduction to “reset” territories.
- 🐟 Add new fish at lights-out to reduce chasing.
- 🪞 Use a mirror temporarily to redirect aggression from cichlid males.
- 🧱 Tank dividers/breeder boxes for high-risk pairings the first 24–72 hrs.
- 🎭 Dither fish (peaceful schoolers) can calm shy/territorial species.
- 🍽️ Feed residents just before release to distract.
🧼 Biosecurity & Tools
- 🪣 Dedicated QT tools; label buckets/nets.
- 🧴 Disinfect contact tools between tanks (e.g., dilute bleach, rinse, dechlorinate, dry).
- 🧤 Handle with clean, wet hands or a soft net; avoid rough nets for delicate fins.
🌊 Special Cases
- 🦐 Shrimp/snails: Copper sensitive; always drip acclimate; match TDS; remineralized RO for caridina.
- 🌿 Planted blackwater setups: Tannins lower pH—match QT water to avoid swings.
- 🧪 African cichlids: Higher pH/KH; use aragonite/crushed coral; add in groups to spread aggression.
- ❄️ Coldwater fish (goldfish): Prefer cooler temps; heavy bioload → oversized filtration & more frequent water changes.
- 🌊 Brackish: Match salinity with a refractometer/hydrometer; acclimate slowly.
📅 Sample 4-Week QT Timeline
- Day 0–2: Acclimate; lights low; test daily; tiny feedings.
- Day 3–7: If eating, consider deworm #1; continue observation and testing.
- Week 2: Evaluate; if flashing/mucus → treat for flukes/external parasites.
- Week 3: Deworm #2 (if your regimen calls for it).
- Week 4: No symptoms, steady appetite, stable tests → schedule transfer to display.
🧾 Quick Checklists
🧰 New-Fish Toolkit
- 🧴 Water conditioner (binds chlorine/chloramine; optional ammonia binder)
- 🌡️ Thermometer, 🫧 airstone, 🧊 spare heater
- 🧪 Liquid test kit + strips for quick spot checks
- 🧰 Airline + valve for drip acclimation
- 🪣 QT-only bucket/net/siphon
- 💊 Core meds on hand (ich, broad-spectrum antibiotic, anti-parasite, methylene blue, salt)
🚩 Red Flags During Acclimation
- 🫁 Gasping after transfer → add aeration, check temp/ammonia.
- 🧽 Intense flashing → suspect parasites; review QT meds.
- 🍽️ No eating after 48–72 hrs → try live/frozen foods; reassess stressors/parameters.
⚡ Golden Rules
- Quarantine first—it protects your whole collection.
- Match temperature & chemistry, not just temp.
- Never add store/shipping water to your tanks.
- Observe, test, record—data beats guesswork.
- Be prepared—keep a stocked fish medicine cabinet like you would at home.
