Just a quick response to answer a question (sort of anyway) that was
brought up during this discussion re pheromones.
Yes. They are sex hormones. But... they are present in all groups of
fish, including egglayers and marine fish. A couple of years ago I read a
paper on angelfish (Pterophyllum scallare) that studied the cues they use
in reproduction/pairing off. I'd like to give you all the complete
reference details, but it's in a box somewhere, as is the rest of my life
at present, and I do not have the time to unpack everything to go looking
for it (sorry). :-) Anyhow, the study found that angels do indeed use
chemical signals to indicate reproductive readiness. They also use visual
cues, but these are not as important.
>From my various readings, I too have found many references to the
production of hormones by young fish that can build up in aquarium
situations and stunt fry growth, but I'll be damned if I know where any
of those references are at present. The cichlid breeders I know that get
the best growth on their fry also do the most frequent and largest water
changes. Food for thought.
Julie Zeppieri (RSG) <><