Sure sounds like blossom end rot.

Is this something you can fix? Is the fruit still edible? Any other thoughts here?

No it is not something you can fix once it happens. Remove and toss those fruit. If you can fix the watering issue then the later fruit should be ok. But It is often a chronic problem with growing in containers as it is difficult to stabilize the soil moisture levels. That is one reason why using a much larger container is recommended.

If you go over to the Tomato growing forum here you can learn much more about this and how to prevent it. I linked the FAQ on it below.

Dave

Here is a link that might be useful: Tomato Forum FAQ and BER discussions

Thank you! Do you I have to scrap all that fruit? Or can I cut it off when ripe? Was this caused by lack of water? Or is it something else?

Apply some lime around the plants, and water it in thoroughly. See the link.

Here is a link that might be useful: blossom end rot

Do you I have to scrap all that fruit?

Have too? No, but most find that fruit with BER tastes "off". Some argue you can cut out the bad part and eat the rest but the bacteria infection in the area normally doesn't make eating it worthwhile.

Was this caused by lack of water? Or is it something else?

That is all explained in the links I posted for you above. Basically it is caused by a poor distribution of calcium throughout the plant as it develops. The transportation of calcium is totally dependent maintaining consistent soil moisture levels throughout the fruit development stages. In containers, especially small containers, that is very difficult to do. There are other contributing factors too - all discussed in the links provided.

Apply some lime around the plants, and water it in thoroughly. See the link.

Sorry but all the studies show that applying lime AFTER the problem develops does not help because lime is so slow acing. Applying it, if needed, BEFORE planting can help.

Again this is all discussed in great detail over on the correct forum - Growing Tomatoes.

Dave

The paste type tomatoes seem to be more prone to BER too, I believe.