At first, honestly, probably all the ***** jobs. Sweeping fish room, (in my lfs I work at we have fish room and a dry good section), mopping fish room, squeegeeing tanks, misc small jobs not pertaining too much to fish.
After that, you can be expected to:
- Catch fish with net, bag fish, tie bag
- Move fish from Tank A to Tank B for various reasons
- Do water changes (usually many)
- Do gravel washes
- Algae tanks (scrub/razor off the algae)
- Do various cleaning jobs of tanks (i.e. fix decor, rearrange decor, add decor, siphon uneaten food, slope gravel to back, etc)
- Help customers with whatever they need, this includes:
- Answering basic and advanced questions about fish
- being an expert on all your store's fish, all their habits, sizes, feeding habits, requirements, etc
- Answer questions about their tank/fish (why are they dying, how do I ____, my fish is doing _____ why?, My ___fish is beating up my _____fish why? What fish can I put in ____ tank? etc
- Answer really stupid questions
- Know all your dry goods (food [dry, frozen, live], filters, filter media, lighting, protein skimmers, decor, heaters)
- Receive stock and put them in appropriate tanks and acclimate them to best of your ability
- Feed the store's fish (fun part )
- Check for dead fish and remove as necessary
- Check for sick fish (usually manager does a sweep of fish room and writes down which need treatment, water changes, etc) and treat accordingly, while putting fish listed as NFS
- Maintaning overall tank health and doing regular maintainence on any filters, decor as listed before, etc.
- Various opening duties of store (check dead fish, turn on all lights, depends on store)
- Various closing duties (as above)
- Answer more stupid questions
- Go insane
- Have fun
ranted, sorry. Every LFS is different though, obviously. You'll learn A LOT working in one, and don't be afraid to ask for help! Nothing is worse than giving some customer false info on a fish you don't know (marine in your case) and have them come back starking mad. Ask your co-workers or managers for help, I do it all the time still, I don't know ANYTHING about corals, so if a customer has a question about one, I still go ask my manager. Try to shadow a co-worker helping a customer with marine, it's the easiest way to learn.