Hello friends,
I had a dream today, in that I had a container or a bucket or something like that and I was trying to put all fishes which was small (not very tiny though) of various kinds in another container. Then I saw among them few were dead, so I I was trying to take the dead fish out, and separate it from alive one, to keep it clean and to have room for alive fishes. What does that mean? I appreciate any answers. :)

Dream means are partly universal and partly personal, so the best interpreter of the dream is the dreamer, when the dreamer is thoughtful and in touch with the subtler side of their psychology. That said:

Probably, the removing of dead fish from the living is speaking of some type of discriminating choices which you have to make. Fish and water are often associated with emotions (emotions are fluid, reflective, and can be stormy or calm); note connection with the archetypal symbol of Pisces (water sign) who's symbol is the fish.