Keeping an aquarium clean and your fish healthy isn’t just about filters and water changes—it’s also about having the right treatments on hand when things go sideways.

This list breaks down six must-have water treatments that are beginner-friendly, highly effective, and widely trusted in the fishkeeping community. 

1. Fritz Complete Water Conditioner

Fritz Complete is a concentrated, all-in-one water conditioner designed to make tap water safe and non-toxic for aquarium use. It instantly neutralizes chlorine and chloramine—two compounds commonly used in municipal water systems that are harmful to fish and beneficial bacteria.

Beyond just dechlorination, Fritz Complete also detoxifies ammonia, nitrite, and nitrate by converting them into non-toxic forms. This is crucial during the cycling process or after a large water change when ammonia spikes can happen unexpectedly.

Unlike some conditioners, Fritz Complete doesn’t affect pH levels and doesn’t contain unnecessary additives, making it safe for sensitive invertebrates, plants, and fish.

It’s also safe to use directly in the tank during emergencies, like ammonia poisoning or nitrite spikes. It's gentle enough for daily use with regular maintenance and strong enough to act as a first response during crises.

📌 Helpful Tip: The product may have a noticeable sulfur smell—this is completely normal due to the active ingredients. If you overdose slightly, aerate the tank well to avoid temporary drops in oxygen.

🧪 Dosage: 5 ml per 50 gallons
🧴 One 8 oz bottle treats up to 2,400 gallons

2. Fritz ParaCleanse

Fritz ParaCleanse is a go-to internal parasite treatment, especially for newly imported fish that may be carrying invisible infections. It contains two potent antiparasitic medications: metronidazole and praziquantel.

These work synergistically to treat a range of internal protozoa and helminths, including tapeworms, gill and skin flukes, and hexamita (which causes hole-in-the-head disease in cichlids and angelfish).

The medication is absorbed through the skin and gills, making it highly effective even when fish aren’t actively eating.

ParaCleanse is safe for most community fish, including sensitive species like tetras and loaches. It’s also plant-safe and won’t disrupt your biological filter, so it can be used in display tanks if needed.

📌 Helpful Tip: Because some parasites have long life cycles or exist as eggs that resist treatment, it’s often recommended to repeat the treatment 2–3 weeks later to catch newly hatched worms.

🧪 Dosage: 1 packet per 10 gallons on Day 1 and again on Day 3
💧 Do a 25% water change on Day 5
📦 Each box contains 10 packets—enough to treat 100 gallons (or 5 rounds for a 10-gallon tank)

3. Fritz FixIck

Fritz FixIck is a gentler but highly effective solution for external parasitic infections like Ich (Ichthyophthirius multifiliis), Chilodonella, and Tetrahymena.

It’s made with Gentian Violet—a dye with antifungal and antiparasitic properties—offering a safer alternative to traditional Ich treatments that often contain malachite green or formalin, which can be toxic to invertebrates and sensitive fish.

The medication works by interfering with the parasites’ ability to attach to the host, ultimately killing them during their free-swimming stage. It’s safe for use in tanks with scaleless fish like loaches and catfish, and even with shrimp and snails if dosed cautiously.

📌 Helpful Tip: Always remove carbon or other chemical filtration during treatment and temporarily take out decor you don’t want stained purple. Raising the tank temperature (82–85°F) can speed up the Ich life cycle, making the treatment more effective.

🧪 Dosage: 5 ml per 10 gallons on Days 1, 2, 4, and 5
💧 Water changes: 25% on Days 3 and 6
🧴 One 16 oz bottle treats up to 946 gallons

4. Mardel Maracyn

Maracyn (by Fritz) is a well-known antibiotic treatment for bacterial infections, especially those caused by gram-positive bacteria. It contains erythromycin, a broad-spectrum antibiotic used to treat symptoms like fin rot, popeye, cloudy eyes, mouth fungus, and body ulcers.

These infections are often secondary to stress, injury, or poor water conditions, and Maracyn acts quickly to stop them from spreading.

Maracyn won’t affect your beneficial bacteria and is generally safe for both freshwater and saltwater setups. It’s also commonly used in shrimp tanks and breeding tanks where infections can quickly spiral.

📌 Helpful Tip: Complete the full 5-day treatment course, even if symptoms improve early. Ending antibiotics too soon can lead to resistance and relapses. You can combine Maracyn with Maracyn Two (targets gram-negative bacteria) for broader coverage, especially when the type of infection is unclear.

🧪 Dosage: 1 packet per 10 gallons daily for 5 days
📦 Each box contains 10 packets (one full course for a 10-gallon tank)

5. Fritz A+ Aquarium Salt

Fritz A+ Aquarium Salt is a high-purity, all-natural salt made without additives or anti-caking agents. In addition to supporting electrolytes and gill function, it’s an essential treatment option for parasitic infections in shrimp, such as vorticella and scutariella japonica. These parasites can be hard to detect until symptoms become visible, like fuzz near the gills or lethargy.

Salt dips can be life-saving when done properly, shocking and killing parasites without harming the shrimp. For severe or persistent infections, a hospital tank with gradually increased salt concentration can be used.

📌 Helpful Tip: Salt is harmful to most aquatic plants, so never treat your entire planted display tank. For dips, always monitor shrimp closely and remove them immediately if they become limp or motionless.

🧪 Method 1 (Dip): 1 tbsp salt per 1 cup of water; soak shrimp for 2–3 minutes; repeat every 48 hours for 3–4 sessions
🧪 Method 2 (Hospital Tank): 1 tbsp per 5 gallons (can go up to 1 tbsp/gal gradually); change 20% water weekly
🧂 Use only non-iodized salt meant for aquariums—not table salt

6. Fritz Expel-P

Fritz Expel-P is a dewormer that uses levamisole hydrochloride, a compound long used in veterinary medicine for nematodes and roundworms. In aquariums, it’s ideal for fish and shrimp suffering from internal parasites that cause bloating, weight loss despite eating, white stringy feces, and overall lethargy.

Unlike some treatments that only kill worms inside the gut, levamisole paralyzes them so they detach and are expelled by the fish or shrimp. It’s especially useful in quarantine tanks or for routine deworming in imported livestock.

📌 Helpful Tip: Levamisole breaks down quickly in light, so turn off aquarium lights during and shortly after treatment. After 24 hours, do a water change and siphon the substrate to remove expelled parasites before they decompose and spike ammonia.

🧪 Dosage: 1 packet per 10 gallons on Day 1
💧 Perform a 25% water change on Day 2
📦 Repeat treatment in 1 week for full parasite life cycle
📦 10 packets treat up to 100 gallons (or five rounds for a 10-gallon tank)

Be Ready for Anything in Your Aquarium

When something goes wrong in your tank, acting fast can make all the difference. These six treatments are like a first-aid kit for your aquarium—each one ready to solve a different problem, from tap water conditioning to parasites and bacterial infections.

The key is knowing what each treatment does and when to use it. By keeping these tools on hand and learning how they work, you’ll be equipped to give your aquatic pets the best possible care and avoid panicked midnight runs to the pet store. Save this list—you’ll thank yourself later.