Hi everyone. I'm new to the world of finny friends (about 7 months in), and I could really use some help. It all started when my fiancé's son took in a very sick betta. After nurturing him back to health and seeing him recover, I was hooked. I set up my own 5g tank with a betta and a couple otos. Eventually I added two mystery snails and an African dwarf frog. Yes, I over crowded! Lesson learned. Anyway, my frog, Snoop Frog, started bullying my betta. I got my new 10g up and cycling asap. Once it was ready (0 ammonia, 0 nitrites, 10 nitrates) I moved my betta, otos, and my fiancé's two otos into my 10g. All was well for a very short time. My betta's tail was in bad shape but he seemed happier. Then one evening his gill was sticking out and in the morning he was gone. The otos seem so happy! But last night I noticed discolored spots on one (columnaris?) and a white nose with something growing on it on another. Also! Snoop Frog (still in my 5g)(yes, I was going to get him froggy friends) now has a lump on the left side of his belly. I'm so devastated! No one seemed sick at all, other than my betta's poor tail, then all of a sudden, everyone from that tank is sick. I feel like I let them all down. I'm not sure how to medicate. Half of my tank is planted in stratum, the other half gravel. The other two otos seem fine.... I want to be a good fish mom so bad. Can anyone help me save these little guys before it's too late?
5g tank: PH 7.8, ammonia 0, nitrite 0, nitrate 20, KH 3, GH 15, 78°
(first time testing GH, KH)
10g: PH 7.8, ammonia 0, nitrite 0, nitrate 5, KH 2, GH 3, 75°