I have a 30 gallon tank housing a group of l144a plecos growing out, as well as an l183. I started with 4 l144a's. but I lost one for some strange reason. First, almost overnight, its tail and fins became torn to shreds for some reason, it just looked like something took a ragged bite out of the tail and fins, (there was even a bit of blood or some kind of redness) but then there isn't any predatory fish or anything in the tank, only plecos. it died the next day. now my l183 has the same thing, except this time it just looks like something took a clean, round bite out of its tail. this too happened overnight, same with the sunken belly, i've been checking on them daily and didn't notice this before. the eyes aren't sunken or anything, he just looks emaciated and then there's the strange wound in the tail. parameters are fine, and I do around 30% waterchanges weekly. temp is around 76-77. I did have a camallanus outbreak in my tanks a couple weeks ago, which wiped out my breeding stock of guppies in the tank, but as far as I know the species of camallanus worm that affects guppies doesn't affect plecos. I treated with levamisole, which cured the last guppy in the tank, but she still died from the stress of the treatment. the stress might also explain the first pleco death, but that still doesn't explain the wounds.