Who's to blame?

Olympia

My poor threadfin's tail got shredded today. I came home to a very scared little fish. (I've been heckling the store to get more, he's all alone, but they haven't been able to. :()
I know it wasn't the cories, or the shrimp. It wasn't the filter intake because there's a pantyhose over it.
Last Friday I purchased 2 African dwarf frogs and 2 bumblebee gobies. Both of which I assumed were slow, peaceful animals. Now, someone has to go..
I'm curious as to who you guys think did this...
I may be able to pick up a 10 gallon for the offenders, otherwise they'd go back to the store.

fish monger

If it's a tank mate issue, it's definitely the gobies. They're sneaky little fin nippers. They could really harm the frogs too. I'd remove them asap.

Jayy

Yes, it's the Gobies. 10 Things to Know About Gobies: Bumblebee Gobies, by Peter McKane

Olympia

Nunus Bumblebee Goby (Brachygobius nunus) Profile
Someone should probably edit their profile, I can't imagine keeping them with guppies, those bright colourful things. :(
Poor guys. I was really fond of them.
I want to keep them, but if I separated them I'd probably want them in brackish which is too much work. >_<

Chesherca

Awwwwww, man! That sucks. . . Poor Mr. Tinyfish! I hope he gets some friends soon. . . and a fast recovery to him. *hugs for Mr.Tinyfish*