Many times writers and experienced fishermen suggest using "natural" bait to entice more or bigger fish. Actually, there are at least a couple of ways "natural bait" could be defined. Normally we would think it would mean something the target fish would tend to eat in its everyday life, as a "natural" course of things. For speckled trout and most other inshore species, this would usually be expected to mean shrimp, small baitfish, or possibly small crabs. While all fish will go after shrimp, flounder tend to have a taste for mud minnows and finger mullet, black drum like crabs and large sea lice, redfish of all sizes often prefer mullet, shad, and crabs.
The other side of the "natural" description of bait is something - pretty much anything - that came out of the water you plan to fish, or even just a similar body of water. Offshore fishermen have long used brined baits such as mullet, mackerel, and flying fish for offshore trolling that often originate several oceans away. Packaged dead bait such as squid often comes from the Pacific, and the most popular of all offshore baits for species from red snapper to king mackerel has long been cigar minnows, also called ice fish. When the Florida inshore net ban took effect many years ago, anglers on the Texas Gulf were struggling to find bait. Most switched to threadfin shad, and just kept fishing.
I have caught speckled trout on fillets off other fish, including my personal largest speck caught on a piece cut from a small shark. Other good specks in the surf were taken with fairly large cut mullet or live 5 - 6-inch "finger mullet." Two of the largest flounder I have caught came on large mullet heads fished on fairly large - 9/0 size - hooks. As I have mentioned in other columns, skipjacks - also known as "horse mackerel" - are good baits for trout and reds. Although my favorite bait for bull reds is a live mullet of 7 - 8 inches, I have also caught or seen them caught on large shad and on squid. I have tried cut pieces of eel bought in a bait shop that came from who knows where, and gotten gaff tops and reds on them. Fishing from a small boat a mile of so off the beach near San Luis Pass I have taken bull reds on big chunks of bonito being fished as shark bait.
One winter many years ago, when red snapper were still our top winter offshore fish, Rene Morales and I enjoyed excellent snapper fishing following the advice of a friend named Danny Stanley who suggested we load the bait well on Renes Grady White with live shrimp. Fished on mono leaders with the "gold" bait keeper hooks commonly used in freshwater, snapper of all sizes and some decent grouper were pretty easy to come by around rigs 18 or more miles off the beach. Winter fish are noted for taking bait tentatively, but when using the live shrimp snapper would inhale them - no finesse fishing here! Many offshore captains carry a box of frozen shrimp to chum for school dolphin, and then switch to pieces of squid for baiting the hooks when the fish "get started". My preference was to always have bags of frozen small menhaden caught in a cast net inshore aboard for chum, and I have had customers who "didnt know any better" thread several small menhaden on their hook and catch snapper.
After reading that some Florida tarpon fishermen considered a dead gaff top with the head and top fin cut off, and rigged by running a wire from the head end through the body to come out near the tail - with the hook on the "head" end and hidden with the shaft concealed and the barbed bend curving outside the body - to be superior for sliver kings to even live bait, I gave this method a try. To date, I have hooked no tarpon I could verify, but have taken several decent surf sharks even while substituting large hardhead for gaff top - and lost some big, unidentified critters.
Some friends and I once talked a co-worker out of trying large carp he killed with a bow in a lake as shark bait in a saltwater tournament. Actually, I suspect he used them anyway, and just didnt tell us when they enticed no fish to hit. On the other hand, I have heard of live goldfish carp of the kind sold for catfish bait being used to catch large ling around anchored shrimp boats, and have used them myself with some success on snapper.
When I was still actively running offshore charters, I liked to take a good variety of bait types on trips when possible. On days when snapper had stopped hitting cigar minnows, a switch to squid would sometimes get them back in the mood. Changing to chunks of cut mullet usually worked even better - and live finger mullet would really get them going. Piggy perch in the live well often mean amberjack or sow snapper in the fish box, and fresh cut bait from anything caught on the trip work better than previously frozen bait, as a rule. Mud minnows will raw strikes from many offshore fish, and are easier to keep kicking in a live well than most other bait species.
Applying this same logic to inshore fishing by trying different bait types, both live and deceased in the course of a day makes just as much sense to me - maybe more - than tossing every lure in the tackle box, even if some of those natural baits might not be usually considered "natural" for the fish you might be seeking.