Is there a specific thermometer to check soup temperature? I'm currently struggling with overcooking small fish so trying to use a thermometer to check water temperature.

The thermometer I currently use

However it says 'meat thermometer' not sure if it can be used to check soup water.  I tried it today(dipped it in soup water) and it seemed to reflect correctly.  

1.Is this thermometer ok or is there one I specifically need to get for soup water?

2. If it makes contact with bottom of pot might it be that it reflects a higher temperature due to pot surface conducting more heat and so are you meant to dip in water but not make contact with bottom of pot?

3.  Even if linked thermometer is ok, is there something which is more appropriate/easy to use when checking soup temperature e.g. something perhaps i could just hang on the pot without having to handle at intervals like the linked one?

Sorry if this is a stupid question.
This is fine, albeit inconvenient
Don't make contact with the bottom of the pot, for the reasons described. Stirring can help make the temperature more uniform. 
You could try a candy thermometer. But most soups aren't sensitive enough that you need to be super careful -- just poking it with a Thermapen or something similar every few minutes is probably more than enough. You can also get an oven-safe dial type thermometer and thread it through a binder clip or similar clamped to the pot, or an oven probe type thermometer (the kind with the probe on a cord). 


For an overview of different thermometer types, see this USDA link.