Dark spots on Carolina Reaper Fruit

[JustinMM]

Good morning from Maine!

I started noticing these dark streaks on some of my Carolina Reaper fruits a couple of days ago (pic).

I'm currently growing 2 pepper plants per 5 gallon container.

I usually water once a day, because the soil has been drying out quickly in the hot weather.

I've been fertilizing about once every 2 weeks with a mixture of fish fertilizer and worm castings (I haven't really been measuring the amounts of fertilizer I'm mixing in with water. Just eyeballing it really).

Any help identifying what this may be would be appreciated!

Thanks.