I have a 33 gallon/ 128 liter tank with 5 Swordtails, 3 Platies (plus one fry), 4 Otos, 2 Zebra Danios, and live plants. I quaranteed all fish for 2 weeks before adding, and the water parameters have always been fine (ammonia, nitirites, and nitrates 0, pH a stable 8.0). A few weeks ago I noticed the first signs of slight fin rot on 2 Platies. They had very small pieces of some fins missing, with some whitish discoloration around the affected area. Since it was so slight, I decided to try without medications first. Over time, they started healing on their own. Other fishes were affected, too, but in a similar, slight way, and they seemed to act normal, and heal without meds. Then one of the Otos seemed to get it a bit worse last week, with almost half of his tailfin missing, but I think that was the same fish that got attacked by the shrimp. Because of him, I finally added some medicine last Friday, Furanol by JBL (active ingridient nifurpirinol) that is supposed to treat bacterial infections like fin rot. Today, after 4 days of medication, as it says in the directions, I changed 50% of the water and added activated carbon in to the filter. As I was doing this, I noticed one of the Swordtails had a new slight sign of fin rot I didn't see yesterday. Then I noticed 2 of the Swordtails have a couple of light colored patches on their body, possibly velvet? They still act normally, as do the other fish, and the livebearers do NOT have clamped fins. But I'm getting a bit desperate now, like I must have done something wrong to suddenly have all this hitting my tank (of my 3 tanks, this seems to be the only one affected). Apparently Furanol didn't work for the fin rot, and now I'm also having another disease, possibly velvet. Any ideas? Salt? I also have medicine called Punktol in storage that's meant for Ich and Costia (?) that I've never used. I don't think I can raise the temperature in the tank up to 30C, because Otos supposedly can't handle high temperatures, but can they handle salt?
Edited to add: The affected areas in the 2 Swordtails' bodies could possibly be signs on attack: those 2 particular females seem to be acting quite territorial and aggressive towards each other all of a sudden.
Edited to add: The affected areas in the 2 Swordtails' bodies could possibly be signs on attack: those 2 particular females seem to be acting quite territorial and aggressive towards each other all of a sudden.
