Rudy's query prompted me to ask along similar lines:

Are there any 'routine' methods for determining the 'genetic' sex of
individual larval fish eg chromosome examination. We would like to know
what the individual's sex really is before judging the impact of endocrine
disruptors on fish later in life. By routine, we mean capable of being
applied to many fish at modest cost with no esoteric equipment.

Many thanks, Rick Leah

ps Rudy, sorry we cannot help with your query.

>Hello everyone,
>
>While doing logic checks in FishBase, I came across museum collection
>records for eggs and larvae which have sex (i.e. female/male) attached.
>The question is: are there fish species where sex can be determined at
>such an early stage?
>
>Thanks for your help.
>
>Rudy
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