A little history first...I have a 10 gallon I tore down after a bacterial infection about 6 months ago. I set it back up using the Walstad Method. My betta, 1 ADF, and a nerite snail survived.
After letting the tank cycle and settle, I bought 2 baby ADF frogs 2 months ago to give mine some friends again. There was one dead baby in the tiny breeder box they had them in at the Petco. I put them in quarantine for 5 weeks, then drip acclimated them over to my 10 gallon.
My betta only flared at them on occasion. Never attacked. The big fat female ADF I already had picked on them a little the first few days. About a week after moving them in 1 baby died. A week later the other. A week later my fat girl I have had for about a 1 1/2 years.
I feed them liberally frozen brine, frozen bloodworms, freeze dried tubifex worms. I have a sand bottom tank for them. My tank always reads 0 ammonia, 0 nitrite, 5 nitrate. My pH is stable at 7.2.
The only thing I can think may have bothered them is I usually keep the temp at 76. I noticed last night it got bumped to 80 after my last cleaning a week ago. Turned it back down last night. This morning my big girl was dead. They had no signs of red leg I could see. They all started hiding a lot a few days before dying.
I was going to try some pygmy cories in here, but now I am scared there is something wrong with my tank again.
Crappy tank pic...