Fish Supplements

Fish medications work, when they are aimed at the right thing. The problem is that most of what looks like disease in a home aquarium is a water quality problem wearing a costume, and treating it with antibiotics makes it worse by knocking out the biological filter. Before anything on this page goes into a tank, do the boring step first.

Test the water before you medicate

Clamped fins, hanging at the surface, loss of appetite, reddened gills, faded color — every one of those is a classic symptom of ammonia or nitrite exposure long before it is a symptom of infection. Test ammonia, nitrite, nitrate and pH. If ammonia or nitrite is above zero, that is your answer, and the treatment is a large water change and a fix to the cycle, not a medication. Both our stores test water for free, and this one step resolves more cases than the rest of this page combined.

Match the medication to the pathogen

Different categories of medication treat completely different organisms, and a broad guess wastes days the fish may not have.

Antibacterials (kanamycin, neomycin) treat bacterial infections — ulcers, fin rot that keeps advancing, septicemia, dropsy. Kanamycin is absorbed systemically and is the choice for internal infection; neomycin is more use for external, surface problems.

Antiprotozoals (metronidazole) treat internal flagellates, hexamita and the hole-in-the-head complex — typically seen as white stringy feces, wasting despite eating, and pitting on the head in cichlids and discus.

Ich treatments target a parasite with a life cycle, which is why they must be run for the full course rather than until the spots vanish. The spots disappear when the parasite leaves the fish to reproduce, not when it dies. Stopping there guarantees a second wave.

Medicated food beats dosing the tank

For internal infections, getting the drug inside the fish is the whole game, and a medication dissolved into a hundred gallons of water mostly does not get there. A binder product lets you mix medication into food so the dose goes where it is needed. It also spares your biological filter and costs a fraction as much per treatment. If the fish is still eating, this is almost always the better route.

Treat in a hospital tank

Dosing the display tank means dosing your biofilter, your plants, your shrimp and your snails along with the sick fish. A bare ten or twenty gallon tank with a seeded sponge filter and a heater costs very little and is the single best investment a fishkeeper makes. Where you have no choice but to treat the display, remove carbon and Purigen first — both strip medication straight out of the water — and know that invertebrates will likely not survive it.

Finish the course

Under-dosing and stopping early are how resistant bacterial strains develop, and the hobby has a real problem with this. Follow the label duration. Do not combine medications unless the labels say they are compatible. Do not dose prophylactically on a schedule — antibiotics are not a preventative, and routine use guarantees you will have nothing that works when you actually need it.

Bacterial supplements and botanicals

Nitrifying bacteria supplements are for establishing or rescuing a cycle, and they genuinely shorten the process in a new tank or after a filter accident. Botanicals — magnolia and catappa leaves, alder cones — release tannins that gently soften and tint water, grow biofilm for shrimp and fry to graze, and are a staple of blackwater and betta setups. Inexpensive, and a good default in any soft-water tank.

Come in before you buy

Describe the symptoms, bring a photo and a water sample, and we will help you narrow it down. We would rather send you home with a water change instruction and nothing to pay for than sell you a medication that treats the wrong organism. See also drip acclimation and our live arrival guarantee.