How to Set Up a Hospital Tank for Betta Fish

How to Set Up a Hospital Tank for Betta Fish | Aqualista

🏥 A hospital tank is essential for treating sick bettas without harming your main tank — This guide covers tank size, equipment, setup, medication protocol, and when to use a hospital tank.

Why Do You Need a Hospital Tank for Betta Fish?

A hospital tank isolates sick fish, allows precise medication dosing, prevents disease spread, and reduces stress. Treating diseases in the main tank can kill plants, invertebrates, and beneficial bacteria.

Many medications contain copper, formalin, or antibiotics that harm snails, shrimp, and live plants. The Merck Veterinary Manual recommends separate quarantine and hospital tanks. In a hospital tank, you can use lower water levels (reduces swimming effort), higher temperatures (speeds up metabolism), and salt (which kills plants). A hospital tank also allows daily water changes without disrupting a cycled main tank. Always have a hospital tank ready before you need it – setting one up in an emergency is stressful for both you and the fish.

What Size Tank Should You Use for a Hospital Tank?

A 5‑10 gallon tank is ideal. Smaller than 5 gallons makes water quality unstable. Larger tanks waste medication. Use a 2.5‑5 gallon container only for short‑term baths (not extended treatment).

A 5‑gallon hospital tank allows stable water parameters and enough space for the betta to move. Aquarium Co‑Op recommends 5‑10 gallons for most betta treatments. For a single betta, a 5‑gallon tank is sufficient. Do not use a 1‑gallon bowl – ammonia spikes within hours, and temperature fluctuates. If you only have a 2.5‑gallon tank, you must change 50% water daily and monitor parameters closely. For salt baths or dips, a 1‑gallon container is fine for 15‑30 minutes, but not for multi‑day treatment.

📏 Recommended hospital tank sizes – 5 gallons: ideal for a single betta
– 10 gallons: good for larger tanks or multiple fish
– 2.5 gallons: only with daily 50% water changes
– 1 gallon: only for short baths (<1 hour)

Essential Equipment for a Hospital Tank

Sponge filter (already cycled or new with bottled bacteria), adjustable heater (25‑50W), thermometer, air pump, hiding spot (PVC pipe), and lid. Have medications ready.

A sponge filter run by an air pump is best because it provides gentle flow and biological filtration. The Merck Veterinary Manual advises against carbon filters during medication (remove carbon). An adjustable heater maintains 78‑82°F. A simple PVC elbow or clay pot gives the betta a hiding spot – reduces stress. A glass lid or plastic wrap prevents jumping. Keep a separate set of nets, buckets, and siphons for the hospital tank to avoid cross‑contamination. Have basic medications on hand: aquarium salt, Epsom salt, Indian almond leaves, maracyn, and kanamycin.

🧰 Hospital tank starter kit5g tank, sponge filter, 25W heater, thermometer, air pump, PVC hide, dechlorinator, test kit

💊 Basic medicationsAquarium salt, Epsom salt, maracyn (erythromycin), kanamycin, methylene blue, Seachem Prime

Should You Use a Cycled Filter in a Hospital Tank?

Ideally, yes. A cycled sponge filter helps maintain water quality during treatment. However, many medications kill beneficial bacteria. Use a seeded filter, then test water daily and do water changes as needed.

If you keep a spare sponge filter running in your main tank, you can move it to the hospital tank instantly – this gives you a cycled filter. Aquarium Co‑Op recommends this method. However, antibiotics (maracyn, kanamycin) and salt (above 0.2%) can kill nitrifying bacteria. In that case, you must do daily 30‑50% water changes to control ammonia. Test water twice daily. Use Seachem Prime to detoxify ammonia between water changes. For short treatments (3‑5 days), you can use an uncycled tank with daily 50% water changes.

🧪 Tip: Keep a small sponge filter in your main tank sump or behind decorations. When you need a hospital tank, transfer that sponge – it is already cycled.

How to Set Up a Hospital Tank Step by Step

Fill with dechlorinated water, add heater and sponge filter, set temperature to 80‑82°F. Add Indian almond leaves and a hiding spot. Transfer betta using a net. Do not use substrate or plants.

Step‑by‑step: 1. Clean the hospital tank with hot water only (no soap). 2. Fill with dechlorinated tap water (Seachem Prime). 3. Install heater and sponge filter. Set heater to 80°F. 4. Add a PVC pipe or small terracotta pot for hiding. 5. Add 1‑2 Indian almond leaves for tannins (calming). 6. Let the tank run for 1‑2 hours to stabilize temperature. 7. Test water: ammonia and nitrite should be 0 (if using seeded filter). 8. Acclimate the betta by floating the cup for 15 minutes, then add small amounts of hospital water every 5 minutes for 15 minutes. 9. Gently release the betta. 10. Begin medication if needed. Do not feed for the first 24 hours to reduce waste.

📋 Quick setup checklist: Dechlorinated water ✔️ 80°F ✔️ Sponge filter ✔️ Hiding spot ✔️ Lid ✔️ Thermometer ✔️

What Water Parameters Should a Hospital Tank Have?

Temperature: 78‑82°F (raise to 82°F for ich treatment). Ammonia and nitrite: 0 ppm (test daily). Nitrate: <20 ppm. pH: 6.5‑7.5. Use Prime to detoxify ammonia between water changes.

In a hospital tank, water quality can deteriorate quickly because the filter may not be fully cycled. API test kit should be used twice daily. If ammonia reaches 0.25 ppm, do a 30% water change. If treating with salt, salt does not remove ammonia – you still need water changes. For nitrite spikes, add 1 teaspoon of aquarium salt per 5 gallons (salt blocks nitrite uptake). Maintain temperature stability – fluctuations worsen disease. Do not change more than 50% of water at once unless ammonia is very high (>1 ppm).

📊 Hospital tank water targets – Ammonia: 0 ppm (if >0, water change)
– Nitrite: 0 ppm (add salt if present)
– Nitrate: <20 ppm
– Temperature: 80°F (82°F for ich)
– pH: 6.5‑7.5 stable

How Long Should a Betta Stay in a Hospital Tank?

Continue treatment for 5‑10 days after symptoms disappear. For fin rot, treat until new fin growth appears (usually 7‑14 days). For parasites, treat for full medication course (often 10 days).

Stopping treatment too early leads to relapse. The Merck Veterinary Manual advises completing the full course. For ich, continue treatment for 10 days after the last spot disappears. For fin rot, continue salt and clean water until you see clear, smooth fin edges (not black or red). After symptoms resolve, move the betta back to the main tank only if the main tank is disease‑free and water parameters are perfect. If the main tank was the cause of illness, fix it before returning. After moving back, observe for 48 hours.

🚨 Do not: Return a betta to a main tank that still has ammonia or nitrite. The weakened immune system may relapse immediately.

Can You Use a Hospital Tank for Multiple Sick Fish?

Only if all fish have the same disease and are compatible. For bettas, never house two males in a hospital tank unless separated by a divider. Treat similar species together only with caution.

If you have multiple bettas with the same illness (e.g., ich), you can treat them together in a larger hospital tank (10‑20 gallons) with a divider. Bettafish.com advises against mixing species due to different medication tolerances. Always quarantine new fish together, but if one shows symptoms, isolate it immediately. For a betta sorority, you can treat the whole group in a 20‑gallon hospital tank if all are sick, but ensure adequate hiding spots. After treatment, disinfect the hospital tank with a 10% bleach solution (rinse thoroughly) before using it again for a different disease.

📋 Recommended hospital tank supplies (nofollow):
• Sponge filter
• Adjustable heater 25W
• API Freshwater Master Test Kit
• Seachem Prime
• Medications (maracyn, kanamycin)

📚 Explore more betta health and treatment guides: ← Main Betta Hub (T1) Disease Hub (T2) You are here Using aquarium salt Popeye treatment Columnaris treatment Fin rot guide

📊 Hospital tank differences from main tank

Feature	Main tank	Hospital tank
Substrate	Yes	None (bare bottom)
Plants	Yes	No (medications kill plants)
Decor	Complex	Minimal (hiding spot only)
Filtration	Fully cycled	Seeded or uncycled with daily changes
Water changes	Weekly 25%	Daily 30‑50% (during medication)
Temperature	78‑80°F	Often raised to 80‑82°F

📖 References & further reading
• Merck Veterinary Manual – Hospital tanks
• Aquarium Co‑Op – Hospital tank setup
• Bettafish.com – Hospital tank examples
• API Freshwater Master Test Kit