best name for a better SEO

I am building a new website but can't decide about the domain name.
This site is about exotic/gold fish breeds and the two possible names so far are:
"exoticfishbreedswiki" or "goldfishbreedswiki" (I already have the "dogbreedswiki" and "catbreedswiki")

Is there a way to know if most people search on google for "exotic fish" or "goldfish"?? What's your suggestion?

 

Use these -
https://adwords.google.com/select/KeywordToolExternal
http://www.google.com/insights/search/#

 

freekeywords.wordtracker.com will also be used

 

IMO the domain is a little bit long,
if you cannot find a good keyword for the domain,
i would prefer to choose a brandable domain instead.

 

yep , the domain has along keyword ..but i prefer that than simple letter .
personnally i will choose : goldfishbreedswiki"

 

If you can do away with breed word in the domain you may get a relevent and shorter domain

 

i will prefer goldfishbreedswiki ..... it because there is more SE on google ......