Alright. I'm fairly new to the whole tropical fish keeping hobby. I have a 29 gallon community tank that has not had one casualty for 6 months- up until now.
It first started after i had performed a rather large (30%) water change on my tank, and the fish were probably stressed out.My 2 zebra danios i had used to cycle this first tank had reddish, rather inflamed gills. I didn't notice until almost a week later when i put both danios into another tank i was planning on starting up. I noticed the red gills now on both the danios, and also noticed they had trouble swimming against the current of the output tube. They also weren't eating, and although i suspected they were sick, I went with believing that they were just tired and thought i'd wait overnight to see if they got better.
The next morning, they were dead. Both the deceased danios had red almost purple gills and a reddish blotch on their anus. I thought that they were stressed and that the tank change, followed by cycling a new tank was too much stress and they had died; however, this was not true. I let the water sit for almost 2 weeks just in case there were some trace chemicals that could have also hurt the danios and then i went to a fs nearby and got 12 giant danios to cycle it faster. (they said that once the tank was cycled i could return the fish for store credit.) To date, they are still doing fine, so the zebra danios must have been previously sick.
When i changed the water, my dwarf gourami seemed a little stressed, and was hiding in a little cave for the majority of the time. When I was feeding, he wouldn't eat, and would remain in his cave. After everyone else had finished eating and had come down, then only he would come out and swim around for a little bit before some other fish, even the tiny neons, swam within 5 inches of him, and then he would dart back into his little cave. In the beginning, I would sometimes manage to get a few flakes and he would eat them, but after a while, he would never come out. One thing I noticed was that he was swimming rather upright in a sort of limping manner, maybe because of the fact that his tail was bent down, almost to the extent that it was vertical. I did recognize this as injury, but did not know how to treat it.
Simultaneously, One-and only one, of my neons was swimming in front of the filter intake tube and barely swimming away in little jerks as if the pull was too strong. He, too, was swimming upright, but I hadn't yet associated this with the gourami. I knew this wasn't normal, but I assumed the fish was fine, the filter pull was just too strong. I didn't really know what to do about it, so I just left him alone.
This went on for a few weeks until 2 days ago, where I was looking for the dwarf gourami, and couldn't find him in his usual cave. Looking around a little further, i noticed his tail was stuck in the heater's suction cup clip! I frantically got out a net and slightly nudged the clip and the gourami darted out, but I could tell that his tail was handicapping him a lot. He would frantically swim at an upwards slant, and then drop rapidly. I went to my computer to search it up. When I came back almost 20 minutes later with no help, he was stuck again! I got him out again, but this time, he pretty much fell down, and lay on the gravel. Every few moments or so, he would try to get up and swim for about a second, and then fall again. I finally realized he was in serious trouble, and I had been ignorant all along, thinking it was just shyness. I quickly set up my emergency one gallon quarantine tank and placed him in there, if not only for him to die peacefully.
Around this time, too, i noticed the neon had really not been struggling. It was now swimming on the other side of the tank, away from the filter, but with that same, struggling, jerky motion. I realized, he, too, was probably a goner, and just set him in with the gourami who was lying down in the tank to RIP also. I went to bed after this, hoping they would die at least painlessly.
The next morning, I checked on them and with my hurried glance before work, I assumed they were dead and then went to work without scooping them up and throwing them. When I came back, and gave them a closer look, I realized BOTH were still alive! I took this as a chance to at least travel to my LFS with actually knowledgeable staff to at least have them inspect the fish and find out their cause of death. Unfortunately, due to a very rach and bad driver, I lost the gourami by the time I got to the store.
When the guy saw both of them, the clerk said he could not see a reason why they had died. He offered to flash freeze the still alive neon tetra so it would at least die painlessly. I agreed and went home...
After burying the gourami in my garden, I came here to post a thread to see if you guys could find out. Please help me avenge the death of my fish!