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Re: Molly swimming problem

Subject: Re: Molly swimming problem
by fcmf on 10/11/2020 16:43:33

Thanks, Corinna - this is helpful.

That eliminates another theory I had - some of my own fish lost function of their swimbladder as they approached the end of their lifespan (age 5+) but your molly is still quite young.

From your next scheduled water change, I would increase it to double what you're doing which would be 25% water change weekly. Hopefully that will get ammonia down to 0, keep nitrite at 0, reduce nitrates, and dilute other things that we can't measure but which may be present and contributory (eg any stress hormones). Ammonia and nitrite should be at 0 and nitrates no more than 20ppm above whatever tap water nitrates are, so worth doing a test on tap water nitrate to find out what it is.
It might just be that larger weekly water changes resolve the problem (and that what this molly is suffering from is long-term exposure to a low level of ammonia, with her being the weakest fish in the tank and therefore first to be affected). Let us know how things are a few days after the first of these larger water changes as an improvement might even occur as soon as that.