My neighbor keeps coming over complaining of her guppies being murdered. Today she brought a corpse over and it's entire rear section had been pulled off, leaving its bones exposed. I cannot figure out what fish could be causing this and I don't think her filter intake is THAT high powered to rip a fish to pieces. She has a 29 gallon take with fake plants, smooth pebble substrate and a millenium 3000 hob filter (discontinued). She has several male and female guppies, platys, mollys, and to my dismay a very small goldfish. I do not know why she chose to put such small fish in this large tank or why she chose the goldfish but she did what she did. Any ideas on why they keep dying? My first idea was this 6 inch long BN pleco that was in there which she gave me because I told her it might be him. I put him in my tank with my convicts. 
Any ideas? I'll update you soon with how many of each type of fish are in there.
Any ideas? I'll update you soon with how many of each type of fish are in there.