Not only am I taking the job, but I get a 20% discount on all of their fish and pet products.
Good Luck.
The problem with 'Big Box' retailers (i worked for one in corporate for many years) is their staffing allotments. Most of the Big Boxes work on a 60/40 ratio, meaning 60% of their employees are part-time, while 40% work full time. The benefit to this is that when a store is selling below "sales plan" (meaning not making as many millions of dollars as they're supposed to) they can tell part-timers to stay home. This is why it can be so hard to find an employee sometimes.
What will most likely happen to you, even being the "Fish Person", is that you will inevitably become "Cross-Trained", meaning you will have knowledge of other departments, usually the departments closest to yours.
When the store falls behind sales plan, less people will be scheduled, and you will have to cover multiple departments, leaving you less time for the fish.
Generally at WalMart, this is the reason the Fish Area is so poorly run, not so much because of apathy, but because of staffing issues.
I truly hope this won't be the case for you, as it sounds as if you really care about this.
keep us posted (or at least me!), because I'd like to be proven wrong.