You might need to wait for one of the USA members such as
@Megawatt to answer this, as most of us are UK-based so the regulations are somewhat different.
In the UK if you don't want to use an RCD (our name for GFCI) for a circuit and it meets certain other requirements (no unarmoured buried cables < 50mm that could be drilled/nailed, etc) then you would hard-wire it in to a fused connection unit instead of using a plug & socket.
However, an aquarium is an interesting case as it is almost like a swimming pool, but not for humans! That normally has to have RCD protection in the area and only safe low-voltage stuff inside it. However, my ancient experience of aquariums is they use mains supply for heaters & pumps and often you are arm-deep cleaning stuff. Tricky...
If you had to use an RCD and were afraid of power loss then options are to alarm the system, or to look at auto-recloser RCDs, but they cost a lot.