I have to admit, finding an answer to my constantly dying baby frogs was not easy. Watching five baby ADF's die in a row, has not been a pleasant experience, and considering I am a relatively experienced ADF keeper, it was more than upsetting.
After diligent research, I have finally found out what the cause of these deaths are. Though I am relieved that it was on no part of myself, it is still sad indeed. Its been tough for a keeper like me who keeps things anal-clean and spot on perfect, to check and re check everything I am doing and question what I have known to do for forever.
The culprit is Chytrid Fungus.
This is just one site of dozens that I was finally able to find, that pinpointed precisely the problem.
Symptoms of Chytrid Fungus are disinterest in eating, spastic hyperactivity, falling into non bloat related constant floating or trying to climb out of the water surface (scrambling), paralysis starting with the back extremities, and then death. Dead frogs are either found floating flat on the top, or sink to the bottom belly up.
There are experimental cures, but I didn't know about any of them at the time, but even those are not true cures. My eldest frog likely survived this (she showed symptoms of scrambling to get out of the water) after a frog that seemed fine (quarantined) was introduced and became ill. I treated these frogs on a hope not knowing the cause with Malachite Green, which likely saved the older healthier frog, but not the baby.
All five babies were purchased from two different Petco's in my area in Connecticut. I have now realized, that unless the frog tank they were in in the store was broken down and sterilized, (un-freakin-likely), all future frogs put in it will contract the fungus. Hence why all frogs purchased at different times had the same illness.
This really upsets me. Contact to the store of this problem was met with disinterest, and the look like I had lost my mind. They had NO idea what I was talking about.
I plan in the future to have a frog tank, so likely I will have to find an online source where healthy frogs can be purchased.
I know this post is a bit outdated but I had some disappointing information to share. I discovered that the fungus doesn't just enter your tank on the back of contaminated frogs. When I added my school of bloodfins to my tank, which had two ADFs from a previous tank, the frogs contracted the fungus. Most pets shops have their tanks connected to a single filtration system. Thus, when the ADF tank contracted the fungus, the spores filtered into the rest of their tanks. Just another reason to quarantine and ensure store water doesn't enter your tank.