goldfish mixed into a community tank

Question
I've been taking care and having fish but am a big fan of goldfish.  I have had the attitude when I have mentioned that I have goldfish mixed in with my "community tank", the attitude is one that goldfish should be kept seperate, that they are "cold water fish".  When I read up on them, my understanding is yes, they tolerate colder water but do better with a steady temp. morelike 70-75m degrees.  Anyway, they seem to be doing great.  What is your opinion and what would you suggest I say to those that give me an attitude like I'm a complete idiot!! Thank you so much for your time.  Debbie Swartz

Answer
Debbie,

 Well what they say has truth. Goldfish are cold water fish and while they can be placed in a warmer tank, it is not recommended. Just because you can place them in the warmer tanks, does not mean it is the correct thing to do. If left in warm water their life span will be cut short. Another reason they say to not have them in community tanks is that they do not have a stomach. Everything they eat come straight out as waste which is ammonia. Ammonia will kill the fish in the tank. I would have to say that goldfish should not be housed in tropical tanks.

Almost everywhere you look it will tell you they do not have a stomach. I have added here a couple of websites for you.

http://kokosgol.ipower.com/care.html
http://www.petfish.net/kb/entry/775/
http://www.dooyoo.co.uk/pets-and-animals/goldfish/1010942/