Who Gives A Fish Forums

My Black Molly has been pooping weirdly long strands, almost like white threads. Tank is a 20 gallon, parameters are 0 ammonia, 0 nitrite, 10 nitrate. Temp is 78F, and I feed them flakes twice a day. Anyone seen this before?

I've noticed something similar with my Mollies. What kind of substrate do you have? Mine's gravel, and I wonder if that's part of it.

White, stringy poop can be a sign of internal parasites. Have you treated the tank with anything lately? I'd recommend PraziPro if you haven't already tried it. Also, how often do you do water changes?

Yeah, that sounds sketchy. I had a similar vibe with my Guppies last year. Turned out to be worms. I cut back on feeding for a couple days and dosed with General Cure, and they chilled out. Maybe try that?

Stringy white poop is often a parasitic issue, as others have said. I'd quarantine the affected Molly if possible. Also, what's your water change routine? Consistency there can help prevent stress, which weakens their immune system.

My Mollies had the same thing, dude. I switched to sinking pellets instead of flakes, and it kinda helped. Maybe the flakes were messing with their guts. Worth a shot.

voltix9 wrote: ↑Wed Apr 30, 2025 1:51 am White, stringy poop can be a sign of internal parasites. Have you treated the tank with anything lately? I'd recommend PraziPro if you haven't already tried it. Also, how often do you do water changes?

PraziPro worked for me too. Also, how old is your Molly? Older fish sometimes have digestion issues.

Thanks for the advice, everyone. I'll try PraziPro and cut back on feeding for a bit. Water changes are weekly, about 25%. Substrate is sand, by the way.

Sand shouldn't be the issue then. Keep us posted on how the treatment goes. If it doesn't clear up in a week, you might need to look into other meds like Metroplex.

Yep, Metroplex is solid stuff. Just don't go overboard with the meds, or you'll stress the poor guy out even more. Less is more sometimes.