Hello all, I got and set up my new 36 gallon tank yesterday, and put my fish in (I used all kinda old material from my other tanks to instacycle it) And the stocking plan was that silver dollar/neon tetra one i put up earlier, but i may have added goldfish ??? and a fishes tail looks like this: > but a fish (I dont know which one) bit off the top so its just a slash.... I believe it is the Silver dollar or Red eye tetra, and some other fishes are the same, but less, please help! and what do i do? Thanks, please reply fast.