Question
I bought 2 small golden tench about a month ago.  One has completely disappeared but other one seemed to be doing well.  However over the past couple of days it had starting being on the surface - sometimes almost resting on top of the pond plant pots.  It has been raining alot recently but that is the only major difference that has occured since we put the tench in. Do you think it is ok and if not is there anything i can do to help?!  

Answer
How big is the pond?  What other fish do you have?  Are they ok?  Tench may need more oxygen than other fish.  It's possible that the oxygen levels may be low due to all the rain.  Do you have good aeration?  Also, rain will reduce the hardness and often lower the pH.  I suggest testing the pond's pH and hardness to see how they're doing.  Otherwise, without a definitive reason for the tench's apparent weakening, there's not much you can do.  Almost any problem (water quality, parasites, infections, etc.) can cause a fish to just lay around.  You might want to add some pond salt if you haven't already at around 0.05%.  Salt deters parasites, bacteria, and funguses and sometimes helps ill fish.  You are lucky to have your tench.  We can't get them here in the US.  I hope the one gets better, and the other shows up!