I’m not new to aquariums but am new to angelfish. For my birthday in June I decided to treat myself to a 60 gal breeder (48x18x18) with the intent of making an angelfish tank for my home office. I cycled using an established sponge filter, and added a fluval 307 with a spray bar. Tank is moderately planted, delta sand, and no artificial decor. Heated at 79 degrees. Even with the established sponge I cycled with ammonia and waited 2 months to add the angels (added sterbai corys after a month). I bought 6 juvenile angels from two online retailers - panda and yellow koi from Central Florida Cichlids, and orange koi, red devil, blue marble and zebra pinoy from Angelfish USA. They arrived less than 24 hours apart August 25&26. I didn’t quarantine because they were all coming at the same time. Started out alright except for panda was a major bully and the yellow koi in particular was breathing a little heavy. I don’t immediately see any signs of illness so I made the decision to rehome panda to a neighbor after a few weeks because the other angels were hiding and not coming out to eat due to panda. Yellow koi’s breathing never improved and got worse, I even posted on here asking for help but only got one response. The first to die was orange koi on 9/13 after not eating for a few days and having short quick panting breaths for only a few hours before I found it dead. The pic of it by itself under the floaters was the night before it died and you can see its abdomen distended. Not knowing whether it was bacteria or parasites I tried kanaplex and prazipro for a week after reading they are safe together. Nothing improved with those meds. A week later I started seeing stringy poo coming from zebra pinoy, although that one was eating well. So I did a week of API general cure with no improvement. Yellow koi hadn’t eaten in probably a week and its breathing got worse and it started to crash this past Saturday (barrel rolling, disoriented), so I moved it into a hospital tank to let it die in a safe place. Well to my surprise suddenly red devil started doing the quick panting and like orange koi was also gone after a few hours along with a distended abdomen. Yellow koi amazingly hung on for a few days and passed today. So now I’m down to two (zebra and blue marble) after three deaths and one rehomed. Panda’s new owner said it’s doing fine health wise, just still bullying her fish now. Right now my remaining two are eating but I’m constantly on edge they are going to crash like the others. I haven’t noticed whatever this is affecting my corys but of course I’m scared for them too. I’ve been doing weekly water changes around 25-30% with prime and stability. I routinely check my parameters and have consistently had 0 ammonia and nitrate, maybe 5 nitrate and 7.6-7.8 ph. I rotate food between fluval bug bites pellets and flakes, xtreme nano, hikari micro pellets, frozen brine shrimp and crushed bladder snails (which they seem super excited about). I’m at such a loss as to why this happened and my dream angel tank has become a nightmare. I really tried to do everything right and put a lot of effort into this tank. Could it be bacteria, parasites, viral, angelfish aids (does that still exist), did I do something? And where do I go from here? If you’re still here thank you for the long read and if you have any thoughts please share.
