Off the bat:
Tank Size- 20gal
Plants: 3 Amazon Swords, and 2 Anubias Nanas
Stock: 5 Neon Tetras, 3 Otos, 1 hi-fin skirt tetra, and up until today, 1 Dwarf Gourami.
So, my dwarf gourami had been living in this tank with this setup for about 14 months now and I thought he had been doing very well. His colors had been very vibrant, externally looked extremely healthy. This afternoon he simply...stopped living? I had just seen the tank with everyone alive and nothing out of the ordinary, took a brief nap (45-60min?) and when I woke up, my dwarf gourami was dead at the bottom of the tank.
There were no signs of trauma or disease on the corpse, his eyes weren't cloudy or glazed, it literally looked like he was just playing a highly competitive game of freeze tag with his tankmates.
Recent changes to the tank which may provide some clues(?);
About 1 month ago, I replaced the light bulb in the tank with one of those bulbs for vivid colors, as the bulb I had in there had died, and began experiencing a rather rampant algae bloom; to compensate I reduced algae wafer feedings to my Otos. There has since been a fairly constant steady growth of algae, but my Otos have never been happier and have been keeping the tank looking on the messy side, but in check.
Last week I set up a betta tank on my desk, and moved an amazon sword plant from this tank to the new one.
Has anyone else had a fish simply stop living like this before? I have literally never seen anything like it.