Ich medication and aquarium salt

Ich looks like salt grains on the body and fins. One medication, dosed for the real water volume, with carbon out, clears most cases.

This page covers what to buy. The ich treatment guide covers the full step-by-step. Keep dosing after the spots fall off.

Why the course runs past the last spot

Freshwater ich is a single-celled parasite, Ichthyophthirius multifiliis. The white spots are parasites under the skin, where medication cannot reach them. When a spot matures it drops off, forms a cyst on the glass or gravel, and splits into hundreds of free-swimming young that hunt for a fish. The medication kills that free-swimming stage.

At tropical temperatures the whole cycle takes a few days. In cooler water it takes longer. That is why Hikari has you keep dosing for three days after the fish look clean. Stopping the day the spots vanish is the usual reason ich comes back.

Before the first dose

Test ammonia and nitrite first. Ich often follows a stressful event, and medicating a tank with an ammonia problem adds to it. Fix the water with a partial water change if the numbers are off.

Take carbon, Purigen, and other chemical media out of the filter. They pull the medication out of the water. Leave the sponge and biological media running so the cycle keeps working.

Work out your real gallons. A 20-gallon tank with 2 inches of sand, rocks, and wood holds closer to 16 or 17. Hikari's directions give the math: length times width times water height in inches, divided by 231, minus what the gravel and decor take up. Overdosing is how scaleless fish get hurt.

Raising the heat

Warmer water speeds up the life cycle, so the medication reaches the free-swimming stage sooner. Most tropical community fish handle the upper 70s to low 80s F for a treatment. API's label says treatment may go faster at 82 F. Raise it a degree or two a day with an adjustable heater and check a thermometer, not the dial.

Warm water holds less oxygen, and formalin lowers it further. Add an air stone on an air pump while you treat. If fish start gasping at the surface, do a large water change and add air before anything else. Skip the heat for coolwater fish like white cloud minnows or goldfish.

Scaleless fish, shrimp, snails, and plants

Corys, kuhli loaches, clown loaches, and plecos are more sensitive to malachite green than tetras or livebearers. API says to give them half the Super Ick Cure dose. Hikari says Ich-X is safe for them at the full dose. Either way, watch them closely for the first few hours after each dose.

Cherry shrimp, Amano shrimp, and snails should not be in the tank during treatment. Malachite green, formalin, and copper are all hard on invertebrates, and some ich medicines sold for marine tanks are copper-based, so read the ingredients. Move the fish to a quarantine tank and treat them there. Ich needs fish to finish its cycle. Leave the shrimp tank without fish for at least two weeks at tropical temperatures so the ich runs out of hosts.

Plants usually get through a malachite green course at the label dose. Salt is harder on them. Some stem plants and mosses melt even at modest salt levels, so in a planted tank we leave the salt out.

Where aquarium salt fits

Salt does not cure ich at the dose on the box. API sells it as an electrolyte and stress support and suggests using it alongside Super Ick Cure. Some keepers run much higher salt levels as a treatment on its own. That works on tough fish in bare tanks, but it is easy to get wrong, and we would not try it with a mixed community.

Our rule: hardy fish like livebearers, barbs, danios, or goldfish in a tank with no plants or invertebrates can take the box dose with the medication. Anything with corys, loaches, plecos, shrimp, snails, or a carpet of plants gets the medication alone.

Salt stays in the water until you change it out. If you dose 5 gallons' worth and then change 5 gallons, add salt back for those 5 gallons only. Adding a fresh full dose at every change builds the level up.

After the course

Do the final water change the label calls for, then put fresh carbon in for a day or two to pull out any leftover dye. Bring the temperature back down a degree a day. Rinse nets and buckets in hot water and dry them.

Then quarantine new fish from here on. Two to four weeks in a separate tank catches ich before it reaches the display, and if it does show up, you treat a 10-gallon instead of your whole tank.