Hey guys, I haven't posted in a couple months. Everything had been going fabulously. Got a second fish and they both had a 10 gal divided in half (each 5). Last night I got a text from the fiancé, Twpsyn (the first one I had gotten back in March) appeared to be injured. He sent pictures and we decided best to move him to the 2.5 half filled so he could get air easily. Swimming was a challenge and he tired quickly. He would frequently rest on the bottom of the tank and displayed clamped fins.
Over the next couple hours this "patchy spot" spread further down his body. It grew further and it reached his gill, which seemed to produce a white mucus on the edge of it with impaired function. By the time he had died, the patch had covered 90% of his body, but never reached his fins, and only a small patchy spot on his head. I can't recall reading about anything that could attack and kill this quickly... the 10 gal will get cleaned today, just in case, even though the gold spotted plec and 2nd betta (on same side) seem happy and well. Nothing had changed in the main tank, filtered, clean..two days ago he had built his first (yes since March) bubble nest.
Any ideas of what could have done this? Parasite, fungus, eh?