Bouncing fish can be used to cover lots of different off-stage trajectories. Jump bouncing fish for high recoveries, drop zone bouncing fish for opponents under the ledge, bouncing fish to the stage for recovering opponents and gives more flexibility in where you let out the kick, and raw bouncing fish at ledge level for horizontal recoveries. Something else you can do with bouncing fish that I like is positioning yourself for edgeguarding, like you can bouncing fish from on the stage into a forward air to get to off-stage opponents efficiently as a movement option. Pros of bouncing fish are sheer knockback and the different options you can cover, biggest con is that you can potentially give up huge positional advantage if you whiff so you kinda have to be confident in it.
As far as aerials are concerned, they each kinda have different uses. Drop zone fair is good to cover lower recoveries, standard sh/full hop fair works for higher recoveries. Ledge drop bair is also an option that can be really good positionally in terms of where the hitbox comes out, but there's some lag in getting off the ledge so it's a slower option. Nair tends to work well because of the lingering hitbox. You can do a falling nair or even a rising nair by running off-stage and rising back up to the stage with a nair. Aerials are less powerful in terms of kb in general, as in they won't be killing as early/sending opponents as far away. Usually do the job to rack up damage though and knock opponents with worse recoveries plus have significantly less commitment than bouncing fish, which are some pretty obvious major pros.
Ledge trumping is pretty good as ledge trump -> bair pretty much always works and puts them in a poor position for recovery/leaves them open to a punish at the ledge if that's what you want to go for. Obvious con is they can buffer a getup option to avoid it, though you can do the mixup which is feint a ledge trump and punish their roll, getup attack, or jump which you can read/react to depending on which option they pick.
Burst Grenade is really good as a safe tool to pressure/limit recoveries. You can position the nade basically anywhere off-stage to cover various recovery positions. Another thing you can do is force an option from the ledge with Burst Grenade and actually trap the normal getup by forcing them to shield, which gives you a free dash grab. If they don't shield, you get a free bouncing fish, and other ledge getup options are much more punishable if they pick those. By far the safest option though it's a bit easier to avoid from what I've seen.
Aerial needles are stellar to get rid of jumps and hit certain recoveries, and can even combo into bouncing fish at high prevents. Trajectory is limited but needles are still really effective for edgeguarding in general. You can also use standard grounded needles to cover horizontal recoveries and force opponents to either air dodge through (which can make it more difficult to recover depending on the character or recover high). Basically, the horizontal trajectory/range is really good. This is a tool you'll want to use often.
