any aro an get a DE. there are plenty of things that cause it. for example if u feed ur aro feeders, the aro goes dashing for them hit there head/eye on the glass tank. If you do feed them feeder, next time flick the feeder a couple of times or cut their fin then feed ur aro. it makes it easier for the aros to hunt them.
another example aros like to look at themselves, or surroundings, so starring at their own reflection at different angles side and bottom of the tank cause DE. if ur tank has no substrate or background chances are higher ur aro might get DE. yeah no substrate is a cleaner tank, but what do u want a cleaner tank or DE on ur ARO.
im not an aro expert, just my lil info, good luck