When placed in water, does this food leach out any oils? I have noticed that trout chow and dry dog food would leave a greasy film on my outdoor pond whenever I fed them to my turtles or koi. Naturally, I wouldn't want to put anything with an oily residue in my aquariums.

Also, are there any less expensive online stores from which I can buy TB? Or must I go through enasco.com?

Thanks very much!

--m