Jose Luis Palazon Fernandez wrote:
> Not really an Histology question ... A colleague ...
> ... diets for fish ...

Dear Jose,
My advice is to tell your colleague to buy a book about
keeping fishes. 
They (small pet books) cost $5 to $10.
If your colleague is wealthy, he could get a computer
for less than $1000 and use Google to find out about
how to feed fishes. 
-- 
-------------------------
John A. Kiernan
Department of Anatomy and Cell Biology
The University of Western Ontario
London,   Canada   N6A 5C1
   kiernan@uwo.ca
   http://publish.uwo.ca/~jkiernan/