There is generally a choice of oxygenators available from the following selection;

 

Callitriche

Ceratophyllum demersum- hornwort

Hippuris vulgaris

Myriophyllum spicatum

Ranunculus aquatilis

Lagarosiphon major -aka Elodea crispa

Elodea canadensis

Potomageton crispus

 

but perhaps only two or three choices at any one time, supply is erratic as there is strong demand.