From what I've read, they can adapt to a static aquarium (though they seem to typically be kept in downwelling/upwelling aquaria), but they're very short-lived (lifespan estimated in months, not years) - they've been able to breed a number of the species (
D. variabilis, D. trunculus, D. obesulus, etc.), but they're typically maintained at low temperatures (~64-67F; with temps going up to ~79F max [typically still lower] to induce spawning) and do require phytoplankton. The larval rearing has been done before, but the reported survival rates have been relatively poor (~5-10%), though the rates go up if they're left in the tank with the broodstock bivalves to ~20-31%, so they seem to have specific needs as larvae (they seem to be touchier about which phytos they get adequate nutrition from than many other bivalves).
This got me looking a bit more at their diet (I apparently neglected to save the reports I'd read at the time of my previous, quoted post about these) - Chaetoceros is typically used as the adult feed; Isochrysis is noted as a poor feed when used as a standalone feed for them. They were able to rear the larvae using a
Monochrysis sp., but the report was published in 1969, so it's not entirely clear if it was actually a Monochrysis species or a different algae that has been assigned to a different taxon by now.
The best survival rates I've seen used
Isochrysis galbana, Pavlova lutheri, Chaetoceros gracilis, and
Tetraselmis suecica in an equal parts blend of the four phytos, but T-iso,
Monochrysis lutheri, Chaetoceros calcitrans, Chaetoceros mulleri, Tetraselmis chuii, and
Skeletonema costatum may confirmedly be used as well. It seems to take about 3-5 weeks for settlement (dependent on species, temperature, etc.), and another ~3 months [Edit: whoops, forgot to finish this statement] for them to grow large enough to be removed from their grow-out tanks (they keep growing pretty much permanently from what I can find).
That said, these are noted for adapting poorly to new conditions for ~1 month; if they survive the first month, they should adapt fine with proper feeding.
References:
https://docserver.ingentaconnect.com/deliver/connect/umrsmas/00074977/v19n1/s12.pdf?expires=1715710956&id=0000&titleid=10983&checksum=588142485BD8273DAFCF7EB3FE64D3AE&host=https://www.ingentaconnect.com (Edit: The Ingenta Connect link above is no longer cooperating, but here's the paper from a different source:)
https://scholarworks.wm.edu/cgi/viewcontent.cgi?article=3123&context=vimsarticles https://www.researchgate.net/publication/265784537_Improving_the_Aquaculture_Propagation_Techniques_for_Restocking_Nourished_Beaches_with_Coquina_Clams_Donax_variabilis https://oceanrep.geomar.de/id/eprint/13513/1/Carstensen.pdf (These last two are good, especially the last one, but they're in Spanish - sorry.)
https://m.riunet.upv.es/bitstream/handle/10251/70242/GARC%C3%8DA%20-%20Cultivo%20y%20reproducci%C3%B3n%20de%20Donax%20trunculus%20en%20laboratorio.pdf?sequence=1&isAllowed=y https://www.mapa.gob.es/es/pesca/temas/acuicultura/hatcheries_if_tcm30-631798.PDF
