I am currently working on an experimental design that requires a larval fish (~ 4mm long) to be affixed on a metal wire tip on its dorsal side. Now, I was thinking of a glue or adhesive to do the job, but it doesn't have to be strictly these, anything that sufficiently attaches the fish to the metal wire tip would do. The glue/adhesive would have to work well on wet surface and, ideally, something that is not toxic. Any advice or ideas are welcome.
You could try methyl cellulose, which my lab and others use. It's not exactly an adhesive, but it is quite viscous. It's common enough that it's in the Zebrafish Book: https://wiki.zfin.org/display/prot/Methyl+Cellulose+Mounting . Obviously, be sure whatever you do is approved by your animal care and use committee.