Getting the eSHa out: How to clean up after treatment

So, you’ve finished the 3-day course. Your fish are looking better, but your aquarium now looks like a scene from a science fiction movie with its glowing yellow or neon blue water. While the colors are a sign the medication was working, you don't want those chemicals hanging around forever. Getting the water back to crystal clear isn't just about optics—it's about giving your fish their fresh "operating room" environment back so they can finish healing.

Here is my tried-and-true process for clearing out eSHa 2000, Exit, and the rest of the gang without stressing the fish.

The "Magic Eraser": Carbon or Purigen

If you have a filter that takes cartridges or has space for a media bag, activated carbon is your best friend. I always keep a fresh bag of high-quality carbon (like Marineland Black Diamond) or Seachem Purigen on standby for "Day 4."

The 24-Hour Rule: Add the carbon to your filter. Within 24 hours, the neon tint should be 90% gone.
Don't leave it in: Carbon gets "full." After 48 hours of cleaning up meds, throw that bag away and put a fresh one in if the water still looks tinged.
Purigen Pro Tip: If you use Purigen, it will turn a dark brown/orange as it drinks up the medication. You can regenerate it, but for heavy meds, I usually just use a fresh pouch.

The "Big Vacuum" Water Change

This is arguably more important than the carbon. I always do a 30% to 50% water change the day after the treatment ends. But I don't just drain the water from the top—I get the gravel vacuum right into the substrate.

Why? Think about the lifecycle of Ich. The parasites fall off the fish and land in the gravel. While the medication kills the ones in the water, it doesn't always kill the ones "sleeping" in the dirt. Physically sucking them out with a siphon is the only way to make sure they don't hatch and start the whole nightmare over again next week.

Wait on the UV Sterilizer

I get asked a lot if you can just turn the UV back on to clear the color. Don't do it. UV light can react with the dyes in eSHa medications. In some cases, it can actually "set" the dye, making it more likely to permanently stain your white silicone or plastic plants. Get the medicine out with carbon and water changes *before* you flip the UV switch back on.

The "Clean Break" Rule

If you realized halfway through eSHa Exit that your fish also has tapeworms and you need to use eSHa ndx, stop. Don't just dump the next med in. Do a big water change and run carbon for at least 24 hours. You want a "clean break" between different treatments to avoid any weird chemical soup that might lower the oxygen in the tank.

Conclusion

Removing medication is just as important as putting it in. By using activated carbon and fresh water, you give your fish the best possible environment to recover from their illness.

Written by Richard James

Aquarist, author, and creator of ShrimpKeeper.co.uk. Helping hobbyists achieve professional results through precision dosing.

View My YouTube Channel & Books →