Black ick in small aquarium!

[TashaLea]

Hi there, so this is my first time on this sight but I am hoping to get a little insight or advice on what it might be and what to do. I do not have a camera so I cannot take pictures. But I have a tank with one betta fish and three african dwarf frogs. They have been living together for several months now without a problem. The five days ago I woke up and the oldest of the frogs was floating, dead. He had a bit of a swollen belly and was blood red near his back legs and underbelly. I couldn't find much on this other than bloaty. I checked all my water nitrites, nitrates, ph, ammonia and chlorine levels. All were normal. I did a 25% water change and left them alone. The next day I came home from work and a second frog was dead. This one had a smaller belly than the first but still a little bloated looking so I now got concerned. I quarantined the third frog in a small cube desk aqaurium we originally bought them in. The miserable little things from Green Earth. The betta I have left in the tank.

I believe it might be ick but cannot find much on it. It is tiny black dots that are swimming in the tank, the size of pepper. I found black ick as a possibilty but is this what could have killed my frogs? Is my third one safe to go back in?

It is a 15 gallon tank. Three quarters full with water. There are the three dwarf frogs and one male Betta. I have two smaller filters, a Zoo Med TC-20 and an Elite mini. There is one heater in there that keeps the tank around 75 to keep them happy. I had no chlorine, ammonia, nitrites or nitrates. My PH was 7.5. It is usually at 7 but not far off. I have river sand in the bottom for the frogs and there are a few fake silk plants and one hiding house for the frogs. And one floating log for the betta.

They have all seemed happy until the first frog died. Now these black dotted infestation is everywhere!! It is mainly floating in the water now as I have raised the temps to 85 to try and cycle it faster. I have IckGuard for Jungle Fish health. Will this cure whatever is in the tank.

And will my Betta be okay with whatever treatments I need to do or should I quarentine him as well and cycle the tank with nothing.

Finally are whatever treatments that need to be done okay to do with the frog going back in afterwards.

Thanks in advance to anyone that can help!! I sincerely appreciate it.