and JDH is wrong for a change.
yes you can get an ABIM fellowship from an AOA IM spot, I I trained at a DO IM residency and am currently a first year pulm-cc fellow at a ABIM fellowship and I know 3 others who've done the same. people will tell you that programs can't take you, that's
incorrect, RRC guidelines clearly state that fellowship programs can take non-ABIM grads into their program as long as they average 75% or more ABIM grads over a 5 year period (page 10). now the caveat is that you can not sit for ABIM boards, I've heard there are exceptions but I can not find one that would apply to this situation, but you still can get board certified through th ACOI/AOBIM, but you have to play their game and do the verification process. I can put my hands on the form right this minute but it's basically same process to get internship approved.
there will be fellowships that will not interview you due to the AOA IM training, but there are friendly programs out there. my personal bias on the AOA pulm-cc programs is that only 1-2 of the programs are at large enough hospitals to justify a fellowship. you can apply for both, but the AOA fellowship process is hap-hazard with no set dates, and I was going to apply as most apply the fall of your 3rd year, but 1 program (after I contacted them about the dates) changed the timeline without notifying me and I by pure luck emailed them the day before and was old then, thankfully I didn't want to go there anyways.