Erythromycin or Interpet No 9 Anti-Bacterial Treatment for Internal Bacterial Infecti
After having picked up a few Endlers from a nevertheless reputable aquarium chain store I've suffered a chain of repeated fish losses in my previously stable display tank, that overall certainly seem to indicate an internal bacterial malady, with symptoms including dropsy. Unfortunately I'd been changing some things with my filtration which resulted in quite high nitrates for at least a week when I was away. I have the nitrates cleared up to below ten now, but I lost another fish still, which was likely weakened from that period then.
I'm not terribly keen on taking a Darwinian approach now, and would prefer to resort to medicating to try to clear this apparent bacterial infection up. I now have some Erythromycin and Interpet No 9 Anti-Bacterial Treatment for Internal Bacterial Infections on hand, but I'm not sure which might be better to try and use. Neither is supposed to harm the good bacteria, plants, or fish, but I'm never 100% comfortable with such medications. The Interpet product contains formaldehyde and methanol, never good, but it is supposed to treat the specific maladies I'm experiencing currently. I also have one cherry shrimp and a snail, and I'm not sure how well they'd take either treatment. I could take them out during treatment, but then I'd just risk reinfecting my tank as soon as I put them back in so I'd prefer for them to be treated as well.
And I'm in the process of setting up a quarantine tank finally. Would either of these be a good idea to use as precautionary medications for new fish? I'd had an experienced hobbyist here recommend a course of Levamisole and an anti-bacterial treatment for all new fish.