Jar with Fish

[ssbill]

It looks well painted and with this mark it isn't trying to replicate a Qing piece. Republic period?

[ssbill]

one more

[Stan]

I don't think they would have used a four character Tonghzi mark, it would have been written with a six character  Zhuanshu mark.
Not to mention the mark looks like it was stamped and the black characters are to black with no fading, and the fish look to realistic. I would say this is late republic period.

[peterp]

The whole bottom shape looks newer. The first of the four characters on the side is ? which is a simplified character from after 1960. The traditional character would be ?.