Perhaps with an Eelgrass meadow? It would require a DSB though.
https://gulfofme.com/all-sea-life/eelgrass-clumps-aquarium-substrate-zostera
A clingfish would be an odd and very personable addition as well. They might eat very small fish and invertebrates.
They have the Skilletfish (which is a clingfish) (
Gobiesox strumosus) here:
https://gulfspecimen.org/specimen/fish/boney-fish/ (Minimum order cost is $70, only for animals)
They occasionally have the Stippled clingfish (
Gobiesox punctulatus) on Liveaquaria's Diver's Den (labled as the Caribbean black clingfish and misidentified as (
Arcos rubiginosus)).
Finally, if the flow in your tank isn't too high, you could try to add a group of juvenile Inland silversides (
Menidia beryllina). They grow up to about 10 cm, so they probably couldn't be permanent residents.
http://www.mblaquaculture.com/content/organisms/menidia_beryllina.php
Edit: These are all native to the coldwater/temperate East Coast of the U.S.