Hello, our little african dwarf frog Maple is sick.

She usually lives in a 10 gallon long tank which we keep filled up a little over half way (about 6 gallons of water) to make it easier for these little guys to swim up. She shares the tank with 3 other ADFs, no other species.

I noticed her odd behavior yesterday. She was acting extremely skittish whenever the other frogs came close. When she would move away from them it was accompanied by a weird spin she would make while swimming away. When trying to feed her she would also just swim away from the food instead of eating it. I will include a link to a video below to demonstrate this behavior.

Upon inspection she has a red streak near her left eye. I couldn't tell whether it was an external injury or something internal, but since we keep the tank clear of anything that could be sharp I can't imagine what could have caused it. The frogs themselves can get a little nippy over feeding time but I haven't seen any of them ever actually injure another.

I have moved her out to her own tank for now. I did a water test before the move and things seem okay. pH right at 7, 0 ammonia, 0 nitrites, nitrate levels is somewhere between 10 or 20 ppm (I'm awful at reading them.) It had been a week since their last water change and they were due for one, which I've since done. We have a small water heater for them, the temperature is kept between 76 - 80 degrees Fahrenheit and we have a gentle filter. Her diet alternates between frozen brine shrimp and pellets

Some more details for anyone kind enough to help and interested. We got Maple along with two other frogs back in February. We kept them in quarantine for 60 days before joining our other frogs, Darby, who we've had for over 3 years now, and Glenn-Peter who's been around since the end of December. A few days before quarantine was up, the male frog in the group of three became sick with what seemed to be bloating issues and later redness in the limbs, underside and head. It struck quickly and he passed within 24 hours. The water parameters at that time all were normal as well, and the other frogs never exhibited any signs of illness. We kept them separate for another week before joining them together and until now all has been fine.
Furthermore, we got another frog along with Glenn-Peter who also passed away about a month into quarantine. It was hard to tell what happened with her because they are leucistic dwarf frogs and I couldn't notice any redness, but there did appear to be some bump on the underside of her jaw.

Image of the redness by her eye.
Name:  Maple eye.jpg
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Video of the spinning behavior.