Flounder are around in the summer in Tampa Bay, but the fishing for them is slow. It usually picks up in the fall to early winter. Regarding live bait, two excellent baits are live shrimp and Creek chubs.
You can fish them on a fish-finder rig or on a jighead. Some anglers like to freeline the shrimp with a split-shot on the leader. Personally I have had the best luck with a shrimp or creek chub rigged on a jighead. The reason is that flounder sit on the bottom hiding and waiting to ambush their prey. So the bait has to be on the bottom, and with a jighead you can get down on the bottom and have a much better feel when a flounder takes the bait, rather than a fish-finder rig or freelining with a split shot.
I don't bounce the jig as much as I drag it along, always staying in contact with the bottom. A flounder's bite is usually pretty soft and detecting it can be difficult. Many times I think I have picked up some grass, or I feel some weight at the end of my line. So watching your line is a key -- if it starts slowing moving against the tide or it jumps -- there's a good chance that a flounder on the other end.
I like to use 15-lb. braided line because it has no stretch and you can not only feel your bait dragging along the bottom, but also the light bite of the flounder. I like the Hi-Vis color because you can immediately see your line against any background and in any conditions. I use 20-lb. fluorocarbon as my leader.
As far as where I would start looking for them, I like edges of channels, passes, cuts, grass flats where the habitat changes from grass, oysters, rocks etc., to a dropoff edge of sand, mud or soft bottom. All the public reefs and wrecks inside Tampa Bay are good for flounder along the edges. There are some pretty big flounder along the dropoffs next to these reefs and wrecks. Work the bait with the movement of the tide. Cast up-tide and let the bait drift down along with it. It will keep it along the bottom, and it will also drift by the position in which they ambush their prey. Once you catch a few, mark that area on your GPS. You can bet that more will move into that area.
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