It really depends on familiar. Probably the best way to have them help is to have them turn into a human (possibly by enchanting the bond). It is hard to imagine how an eel would be able to help in the lab, as it would likely be bound to an aquarium. Someone with a large quadruped familiar would also need a very well designed lab for it to be any else than a bull in a china shop situation.
From experience, in my old group 2 of the mages went splitsies and ordered a talisman what would have their familiar (an owl and a dog) a human like arm to make them useful in the lab...